Hot Starting Problem

[leo]

I am considering buying a 1997 Tdi Discovery which has a problem starting when hot.
It starts fine when cold. When hot the engine turns over but won't start unless it is left for half an hour.
It will also start hot if you disconnect the black connector at the top offside of the engine, count 15 seconds and have someone start the engine straight away when it is reconnected. Is this likely to be a sensor fault ie fuel temperature sensor?