Paul had this problem a few months ago. The car would start when cold then went on to no start when hot then no start at all. You realy need to check the fuel pressure with the correct tool.

This vehicle had no DTC's but fuel pressure was low. The fault was the pressure regulator which is bolted to the high pressure pump held on with three torx bolts and a two wire connector. Take it off and have a look at the "O" ring or swap the regulator for a known good one. These regulators do not come without the high pressure pump according to the dealer, but Andrew Page can get hold of them if you give them the Bosch part number.

Keith