Cutting out once warm

[6ettinold]

Hi all,
Apologies for the invasion, but I have a Fiat Ulysse - albeit a 807/C8 in an Italian themed frock. It is a 53 plate 2.0 diesel non-FAP.
My issue started out as an intermittent fault, but the car cuts-out without fail now, as the temp gauge approaches 90 degrees. It will do this whilst being driven, or sat idling. No eml or warning on the centre display beforehand.
Starter turns, but car will not start. It would restart initially if the battery was taken off for half an hour and reconnected ( with the usual wait for the BSM to reset ). Now it has to be left overnight, presumably to cool down before it will start again. Antipollution fault and EML will then be lit. If left longer ( ie, a day ) both will disappear.
Has done this 4 goes on the trot. Exact same temperature on the gauge when it cuts out.
I have no access to PP, Lexia, etc. I've got bog all chance of driving anywhere to get it diagnosed either.
Was thinking crank sensor - but the temperature is so precise that I doubt it's that. Car does stink of diesel as if it's perhaps overfueling too.
Has anyone got any clues at all please? I'm a hare's breath away from scrapping it.
Any help would be hugely appreciated.
Cheers.