I think it is a mixture of factors too. I've done more testing and whilst it is good 5-10-20 mins after, so far more useable, but if i leave it for 30/40 mins I get the same problem. It always starts but interesting how the time frames have shifted. Perhaps points to time worn compenents.
Thinking back to my white car, although fault seemingly solved it did have a few occassions where it would crank longer than expected though more than 9 our of 10 times it was fine.