intermitant EA fault

Have had a few ideas given to me of the fault so I thought I would post it on the forum to see what happens.
Mostly on a hot day after driving the EA beast around, then parking up to go to shop or pick the kids up at school the dame thing won't restart, the motor just keeps turning over but no start. whats even more annoying is you call the RACV and when they turn up, they tell you to turn the key and the dame thing starts straight away, I think the EA thinks it's a human. Has any one else had this problem. Ive been told that it may be the modulator on the side of the distrubutor, they reckon a change over would be around $300. Anyone out there with any clues??