Thanks for that Ziggy. If you look at the last pic you sent me, you can see that the housing, fn plastic I may add, is held in with the whole fuel injection inlet manifold. It took me three hours of dismantling and jack up the front of the car, to access 4 inaccessible bolts. I've tracked one down in Poland. TH White are looking for the part as well.
Why would Fiat have such a flimsy part connected straight on to the head? Crazy.
Here's a pic.
It is a pain to replace because of the way it's coupled into the inlet manifold.
You say it's flimsy, but it really doesn't bear a much in the way of forces. I would call it good engineering. Failure is rare, if you judge it from this forum.
tbh i've only had 1 leak of the temperature sensor housing, and that was because the seal had rotted away
That was on an 8v which is tight access, but easily rectifyable