T595 Thermostat Alternatives To Triumph Part

Hello,
I have done all the checks, cleaned it and run it a couple of times and my T595 thermostat is no longer working properly (in the 'pan test' the pin extends out under heating, but does not return to its original position). As many of you know its replacement (part number T2102131) is no longer available and rare on eBay. Does anyone have a viable alternative part? (I have picked up some talk on a German Forum of a Mahle TH580 7080773 being suitable and various others are mentioned on the wider net).

Also whilst I think my current thermostat is a lost cause, does anyone know how you attach an O ring to the top of the thermostat (this had a degraded one which extended to both sides of the grooved flange at the top, which I removed) and does this O ring (as distinct from that in the housing) need to be replaced?

If the thermostat is working should the engine management light go off automatically (assuming the temperature sensor is also working!?).

Any thoughts/ guidance extremely welcome.
Thanks.

 

Thanks for your reply Sprint Dave and the thread attached. My understanding is that the T595 and early 955's use a different thermostat. I have some research via Facebook and it looks as though a Chrysler Saturn uses an identical one and this is available from the U.S. via eBay. I could be glorying in that triple again by mid-March.