Edit: Sorry, should have posted this in Oily Bits....No coffee yet.....Please feel free to shift it.

Aloha,
I seem to be getting the old "Baffle them with Bullshit" routine from Allisport!
They sent me a tank for a gems, which takes a cap that looks like it is from a Classic.....They sent no cap.
It has only 2 nipples, and no provision for over pressure blow off.
The last 8 weeks, I have been waiting for them to send their
"New Design" which is supposed to use the existing pressure cap rather than a bayonet style........
It seems they now are under the impression that "Some" P-38s were made with "Different caps".
YEA, Right!
Before this devolves into a trade war, can anyone recall seeing a P-38 with a plain screw on cap?
Here was his response this morning to my sending him pics of the tank they sent:
Comments welcome!

Hi Tom
After seeing the picture that you have sent it looks as if you have the new design which has replaced the original typr as shown in your first picture. The new design should fit the standard cap however we have since found that a few cars were built with a different cap which I imagine yours has. I can send a cap to you asap or we still have a few of the old parts so we could make an old style header tank for you but we don’t have any of the ALLISPORT caps so it would come with a standard bayonet cap.

Please let me know your preference so I can get this sorted for you.

No.

All P38s that I've ever seen have had the black plastic screw-on cap (not bayonet) as used on BMWs of the time too.

+1, it's the same cap as a 5 series BMW of the same vintage. Even the later Classic had a screw on cap (different to the P38 though), they stopped using the bayonet style around 1988.

My preference would be for a return for refund.

I am inclined to agree at this point as they are clearly a bit delusional..........Sad really as they seemed to be a decent company. Their Neil Huggett, whoever he is should not be interfacing with customers as he is clearly not informed enough to do so. Whoever is feeding him erroneous information should, IHO, also be sacked!
Nevertheless, I am giving them a bit more rope, to see just how high they wish to hang :)
Anyone near Ledbury, Herefordshire that wants to pop round and show them what a P-38 tank top looks like?
They need help!
Here is my response to them: (It will be interesting to see how they respond)

Aloha Neil,
Yesterday? Sorry, no e mail, and no spam from you yesterday.
This is a tank, of whichever style, which looks like the GEMS model.
New or old does not enter into it. It is the wrong tank.
FURTHER, the cap for a P-38 Range Rover has remained the same for ALL years in ALL markets from 1995 through 2002.
The tank I ordered has provisions for the Throttle body return line, the radiator air bleed return line
as well as the overflow discharge line. That is 3 (THREE) small nipples by my count. This tank has only 2.
As there is physically no way for coolant to escape in case of an overheat, sending a screw cap would be useless, as the neck
has no provision for blow off.
So, the only way to sort this is to send me the correct tank which I ordered.
I have no idea how you have "since found " anything as i was assured by Jessica that you were changing designs,
thus out of stock, but I would be put on a list......
You further delayed by stating your "Welder was out sick"
By this logic, I have one of the first "New design" tanks manufactured, so there could really be no "we have since found"
I have posted a query on 2 Range rover forums and confirmed that the P-38 has only ever had a Black screw on pressure cap.
In all markets world wide. For your reference this is an PCD000070
So, the only solution that is going to satisfy me will be a replacement tank that matches Jessica's description as using the stock cap.
In other words: The tank i ordered and paid for.
Thank you for your prompt action to resolve this. Your company is highly regarded by the Range Rover community.
I will hope this was just a minor shipping error and can be rectified, and that I will be able to report that your customer
support is as reputed.
So far I have been frustrated, disappointed, and now insulted..........I would really like to be just plain satisfied
Regards,
Tom

Hmmmmmm.
I preparing to order yet another plastic tank, as I have little faith Allisport will do the right thing......I stumbled upon this:

https://www.ebay.com/itm/Universal-350ml-Overflow-Catch-Tank-Radiator-Coolant-Bottle-Header-Reservoir-Set/252783558257?fits=Year%3A2002%7CModel%3ARange+Rover&epid=579925488&hash=item3adb12fe71:g:07sAAOSw32lYroqT

Looks like the bottom fitting is a but smallish, but possibly would work.
being LHD, I have plenty of room to install this shape tank.
For the price, just how bad could it be???
May order one just to see how bad it could be.....At least it comes with a cap!
Cheers!

If you think you've got enough room to fit it, I'd go for it although it might be a bit small. Only other comment I'd make is you'd need to change the cap they supply as that one appears to be marked as 0.9 bar when you need 1.0 bar (although that probably would make a lot of difference).

Well, as it is an "Make offer" listing, I will offer 25 bucks and see what shows up!
How bad could it be?
May just need to have a local shop put on a larger dia bottom pipe....But perhaps not?
It is indeed a lower capacity, and I will not have a float switch, but I do not have one now, even tho I spent 210 pounds!
What the heck!

Looks like Bearmach are selling the Allisport ones (https://bearmach.com/aluminium-header-tank-eu3-diesel-with-bottom-outlet-and-sight-guage-ba-2382) with the sight glass but a generic bayonet cap and not the screw cap that the original one uses. Was going to say I was surprised that Bearmach hadn't told them but I suppose the thinking is that a pressure cap is a pressure cap and the actual design isn't important.

Allisport has ....or had, until their "design change", an customised cover for a bayonet cap. Looked pretty good too.
An outfit in Florida has the tank with sight glass as well. I would have bought from them, but I really wanted the switch version. I am still a bit hopeful they will come through, we shall see.
In the meantime, I found the small round job on Amazon for $19 bucks with free shipping......Ordered one. WCPGW?
Should get it next week, Quicker than anything the folks over there will achieve, I am sure, so will see.

Update:
Things went very quiet after I sent photos, the correct part number for ALL P-38 header tank caps, and told them
they were basically totally wrong to state there was ever an different cap.
After threatening to start a payment dispute with Paypal, they finally got back to me.......
Blamed Covid, of course, and will be embarking upon an emergency Pull-Out-All-The-Stops build of an "Old Style" tank....
This, they promise to get to me ASAP.
With luck, it will be correct........I have asked that they send a photo of it prior to shipping.
Not that I do not trust them, it's just that I ABSOLUTELY do not trust them!
Time will tell.
In the meantime, I will have the $18 Amazon alloy wonder tank in 3 days, and will see if I can get it to slide in there.
I may need to have an 1/2 inch 90 deg elbow welded in the bottom in place of the fitting supplied, but other than smaller volume, it should do the job. Could be a really low cost alternative to ever cheaper plastic knock off tanks.