Interesting, Pete. Here probably is option 2), both my car and the donor parts were unused for a good 3 years, and the spare were indeed in a more damp place. Well ... now I learned besides the mechanical, also the radio needs to work!

Richard (once again) you nailed in the head, it was exactly that. For now I mounted the one that looked more 'alive', and closed everything as I have my parents over next week on visit and it would really pain me to show ONCE MORE AGAIN the car disassembled ... they will not notice a loss of sound in one rear door 😆
I will look into replacement in a later time, when guests are gone!

I have a friend has an old man which works to round up his pension fixing old audio stuff (cassette tapes machines, old amps, speakers, and the like). I have seen some repairs on a sub and a woofer, both "proprietary" designs of German youngtimer cars, whose owners did not want to lose originality, and in both cases the results were satisfactory for a little change. Will pass by and drop the speakers to see if he wants to play ...

Now the next following question would be ... how do you "unfreeze" it? 🙃
Re-cone it would be the simplest answer I can come up with ...

I had never actually given any consideration to how the gearbox "P" works so I also haven't given any consideration about how the vehicle was being held. Silly really, but I suppose that it is a habit going back nearly thirty years !!!

No fault - most people if not all would assume the "P" is just another "gear", like in a manual. Well ... is not 😀

I had not thought about the speaker "seized" ... it sounds extremely funny but hey everthyng can happen. Now that I think, the speakers I pulled from the bin have not been used in a while, so it could be indeed.
Wiring became clearer, especially after I noticed last night I was linking at the wrong page ... I got a Highline system. I think I will chase the "frozen" speaker theory :-)

I got an issue that is keeping me busy and driving me crazy.
Rear right woofer has became nearly silent, you can barely hear it. The midrange in the door card sounds loud as normal.
I replaced the speaker with another three spares I had laying around, with two same effect, with one there is some "movement", but again very low.
Removed the radio and replaced with another from a neighbor, same.
Open up the ISO connectors and swapped left to right the pins (a major pain in the butt), same. Is only that side that gives trouble.
I replaced the amp in the door with another I have laying around, same.
I shortened brutally the cable going through the door, in case it had gone bad somewhere unseen, no improvement.
I tested the speakers with a multimeter, all give around 3.4/3.5 ohm. The midrange in the door card, 2.5 ohm.
I tested the output to the woofer in the door amp, both give around 10Kilo ohm, I do not know if is right, but both are consistent.
I do not know what else to do ....

I am now seeing the ETM and the wiring diagram for the rear door bass speaker looks weird (page 144). Can someone help me interpret which cable goes which way in those connections? I can reroute them to match the diagram, if I can understand it (I am tired today, played with it for three hours after work ...)
Someone has messed around in this car in the past, so something might be out of line. I do not remember if this worked before, but I think it did.

I also use the handbrake always, in all my auto's. The pawl in the parking gear is a weak spot, I see it loading unnecessarily using it to hold the vehicle. Plus I terribly dislike the "clunk" it makes when it disengages, when it has binded with the load of the weight of the vehicle on an incline ....

My procedure is: stop the car - foot on the main brake, gear lever on N - foot on the main brake, handbrake on - foot on the brake, release main brakes, put in P, turn off. Sounds cumbersome, but it takes a second ....
Sometimes I even stop it in N and turn it off, then select P.
For some reason, this has become the norm with the Micra, whose g-box tends to "bind" and selects P with quite an effort ...

I second that, I have been using those clamps as well ... and also a good thing is that if a bolt seizes, is easy to cut it and replace it with a new one, standard sizes!

To bring up to date this topic, some recent journeys

https://1drv.ms/i/s!Aog9VsSxOLcFm1yl5aQvXoS_YDv1?e=3vWeb3

https://1drv.ms/i/s!Aog9VsSxOLcFm2mh8ymmjIV6jA_A?e=1q1wXh

lovely ride, the P38

Make sure the owner read this and comes for his wheel lol

I agree to that ....

No it isn't. It was a 1960's Buick design that Rover bought from them....

Richard, you missed the romantic take on my words ... lol
I meant it as if the relationship between the P38 and the RV8 is like a loving, but sometimes troubled, marriage :-)

... the mythical porous block ...

Thanks for the story, this explains some things I always have wondered. I knew about the Comcast production, and I thought it would be odd not to produce them with top hats, which I to my understanding is the only real solution to an eventual slipping liner ...
I also heard the rumour - and funnily from local mechanics, so imagine how much it has spread - that the 4.0 is a "better" and "stronger" engine because of the material thickness between the bores, but I am like "ah yeah oh ok" .... lol
What I meant in any case is that with simple steps, and well documents, you can resolve the weak areas of the RV8, true or myth to be.
About the heads, I should have specified that if I was to get my engine rebuild, I would do some tune up to them ... :-)

I've said it before and I'll say it again, maintenance is key....

True. Unfortunately, when you buy used, sometimes it can get tricky .... I bought my P38 driven by emotion, not thought, and it costed me dearly.
But the engine ... it is old, tires, 283K km, it has been neglected, it clunks and clonks, leaks oil, eats some antifreeze, but it does not let you down, always pulls. That is why I think in spite of its quirks, it is a loyal beast.
Plus, it is the P38 "unique" engine. It was built for that car, and that car was build for that engine. That remains its signature :-)

I did this to mine when I swapped seat bases, and so far is holding on .... year and a half, and 20k km. Used almost daily.
They sides are still firm. Try it, you got nothing to lose, foam does not get damaged and being steam it dries quickly.

NOTE: edited typo

Why bother when he could just buy one off the shelf? See http://www.v8developments.co.uk/50long.htm, good for 350-400bhp depending on cam.

As I said, here lots of people love to spend endless time working and suffering on questionable ideas. I got used to it ...
But my mate is young (half my age!) he is a programmer which means spends all his day in front of the PC, and likes to spend his free time making up stuff .... oh well, we were young once as well !

There's a Brit living in the US that has fitted an LS1 with 4L60e into a P38 and all it needed was an adapter to mate the GM gearbox to the existing transfer case. He's got everything, BeCM, EAS, ABS and all instruments working exactly as they should too. Overfinch used to fit an American V8 (a Ford I think) into the P38 using the original 4HP24.

This is as I wrote above, possibilities given by each place. Here an LS1 is a mirage. BMW stuff is much more common ...

While the BMW engine from the L322 may not be the best and a lot of people complain about the Vanos system, but if doing a conversion you wouldn't put a knackered old engine in, you'd at least rebuild it first. That way it will last just as long as it would have done when new.

Well, here you are presenting again another valid point: how much does it cost to rebuild an M62 compared to an RV8?
If you make some research, is not exactly a cheap proposition ... and again, some things provide questionable results, for example re-sleeving it in case the Alusil (Nikasil in earlier models) fails.
I do not know prices in UK, but here the rebuild list for a M62 is really a high price.

Ah! and no, no way I would go Diesel if I can avoid it ...

The problem is more that you'll put thousands into a Rover V8 to get it to that state, and its not like its then suddenly reliable. Its still the same engine with many flaws, its just a fresh one. Thats the bit that i'm wary of.

And you right to be wary ... for that you should have never got into a P38, or even a Land Rover in the first place LOL. But we love to have something to deal with every time ....
It is true that the RV8 is an engine with several weak points, but at least they are all well documented and you got plenty specialists that know how to deal with them, after all, is an UK engine and most you guys are in the UK. Abroad in some places might not be that easy. Me here, although in East Europe rebuilding old engines is almost a weekly routing for most mechanics, a very old-school engine such as this, I would not trust anyone to do it.
But there ... after all, one you have sorted a porous block, fitted top hats, machine properly the heads and balance the engine, the rest is really a lesser problem.
And in comparison with having to re-sleeve a BMW lump because the Alusil coating has failed ... now that is the fun!

You can pull a 20 year old M57 out of a scrap E39 and pretty much know it'll just work. It might want a new turbo at some point, but the actual engine is solid. And the same goes for most modern engines. Thus the question, do you spend the time/money making a good Rover V8, or do you instead spend it making some other more reliable modern engine fit instead.

That is a subjective point of view indeed. Is a matter of choosing what problem you want to deal with. For me here, surrounded by people with uncertain projects, changing powerplant would be a matter of several weeks if not months dealing with various people for fab work, electrics connections, and the such, plus my own time, which is very limited. I need my junk to be in running condition, not in an endless loop of technical ecstasy ... for that I already went and started other projects :-(
So for me the answer is easy, stick with the RV8 or change car altogether. Now that is a question ....

Great news!
I had not time these days for my neglected queen, I just gave her a much needed wash ....

Great!
Something I discovered that works with the foam as you said, "gone soft", is to pass them through a steam cleaner, not a vacuum cleaner, but those devices that literally make steam. For some reason, they "regrow" to size after a couple of applications. You have to be delicate in the most "smashed" areas not to break the foam apart, but believe me, it works!

Certainly buying a steam cleaner but such purpose is overkill, but if you can borrow or rent one for the purpose, it pays off!

I've swapped seats and bases on mine and no, I do not recall any settings or calibration. Mount, plug it in, check if works, tighten :-)

To shorten the pump would be tricky, and have to ditch the sender. I'd rather sell it as used part (mind its got 290k km), and get a new one anyway.
There are already tanks made for kit cars and off road vehicles that come with an incorporated sender, and made ready to "fit and forget". No sense to indulge in playing around ... they even accept custom sizes. Made simple :-)

I took some measurements, margin of error +/- 1cm

https://1drv.ms/i/s!Aog9VsSxOLcFm2GNeeOo7cS1pbe1?e=UCvpn9

As you can see from the stepped shape, I believe a tank that can fit in a "box" of say max 560x500x400 mm to be on the safe side, would be sufficient. I will start looking as see what comes up.
As for the fuel, the stepped front part is a trapezoidal shape (it escapes me the name of the "3D" version of a trapeze) max 200x420x560mm, which gives a volume of 47 liters, I believe ample sufficient.
There is no way to fit the OEM pump and sender, as it is positioned in the "high" part of the fuel tank.
A suitable aftermarket replacement will do fine. Anybody knows what is the rating of the OE pump (operational pressure and flow)?
Another benefit of a different pump would be to have a normal fuel filter!
There is plenty space ahead of the fuel tank against the chassis rail, working around some sort of EVAP canister.
I was thinking a cradle like used in the old Mercedes is ideal, as it holds both filter and pump in a suspended harness.