More of a tale for your amusement, as the offending blighter of a sensor has now been evicted from its exhaust bung, and reduced to many small pieces...

My parent's P38 has had a bit of a bad time lately - tried setting fire to itself twice, once with fuel, then with a locked up caliper. New petrol line, entire ignition system, new front-rear brake lines, flexis, rear calipers, disks, pads... and then the bastard still refused to run right. Lean on bank 1 permanently. Lambda sensor looked like the culprit - refused to shift from 0v despite firing on all cylinders.

So... a new sensor it is. Pop the old one out, pop new one in, job done. Or not. With myself under the car pushing with my foot against the spanner, all I managed to do was round off the nut on the sensor. With a bottle jack forcing the spanner upwards, the car was lifting before the bottle jack eventually gave up, and I rounded another side off...

Friend of a friend offered to help - I think this car may no longer be welcome there! Even cherry red with grips, it still wouldn't shift. So, cross member off, exhaust studs all removed, and the centre box clamping plates cut through. On the bench, even more heat and a 2ft bar welded to the remains of the sensor - nope. Eventually, after the welds on the bar broke twice, it started to move with some persuasion from a set of stilsons.

Before it came out though... I noticed something:

I sent that photo to Marty while the sensor was still being massaged, and he said something about gaskets, and I realised... there was never any gasket on this side -_- I guess, had the sensor actually come out without a fight on the car, who knows how long it would have taken to find the exhaust leak, that was likely the problem all along...

But hey. Managed to find a nut that the new sensor threaded onto nicely, which was then welded on top of the old bung. New exhaust studs, a pair of new gaskets (ho hum, totally haven't been here before, prepared for this sort of crap these days), some nice work on the centre box clamps, and one adaptive reset later, it runs properly!

Another of those 5 minute jobs eh Sloth?!
A testament to your persistence as well. I'd have whipped out the disc cutter and chopped off the whole boss/ sensor after the first failed attempt :)
On the plus side, the exhaust must be pretty solid if that amount of force didn't twist it to destruction.

I generally won't give up with something until I've done it... thankfully the others involved seem about the same! Otherwise it would have been rolled out of the unit and I guess round two would be tonight.

Now though I'm more inclined to get on with some of this little list that needs doing:

door latches
remote locking
ignition barrel
head unit
radiator bleed hose
lpg gas hoses
interior lighting led change
sort dash switch lamps
heater box....
heater core
plenum/pollen filter reseal
dry out foam under carpet
shampoo carpet
good clean of dash etc
fit front fogs

and then aesthetics... wing has a dent, front and rear bumpers need respraying, headlining...

On yours or your parents?
That's a bit of a list- you're almost in Project with a capital P territory there. Looks very similar to my list for the black one, only I had more oily bits to do!
While I think about it, when you're waterproofing the plenum, check/ replace/ seal the self tappers that run along the bottom holding the black panel in place.
This is what mine were like. No amount of sealant round filters etc would stop the leak through those holes, hence the PO stuffing all manner of sponges and cloths under the dash :)

On the red one - my parents. I've already done most of those things and more on mine :)

Ah yes, I remember those. When I did my green one and silver one, I took the whole lot off including the pollen filter carriers and ran a bead of sealant everywhere, and then sealed the screws. I think on the silver one I even put a bit on the filter covers, because the foams were practically non-existent.

If you're up this way again at some point then let me know, and I'll give you some new black self-tapping screws - I bought a set of them awhile ago of varying sizes, so as I take rusty horrible ones out, I put new ones in!