Hot start issues

[MPS]

For the first time in 6 years of ownership my car failed to start at the first try from hot yesterday. 2nd time it was OK? Doesn't happen on a cold start though, first thing in a morning and after an 8 hour shift it starts first time.

Any ideas chaps/girls?

The car is AXX engine, 11 years old, 98k miles.

[Flyingscotsman]

I don't know if this is an issue with mk5's but my old mk2 suffered from a heat-soak problem with the starter/solenoid. Basically the low voltage part of the solenoid draws more current than the ignition switch circuit can supply. The problem gets worse as the solenoid coil gets hot, hence hot starting problems. I made a simple fix by adding a 30amp relay (£3 from Maplin) to the circuit.
Cheaper than a new starter motor & easier to fit !

[MPS]

Interesting, thanks. 

[Flyingscotsman]

Next time it happens, see if you can get it to turn over by temporarily connecting a thick wire from battery +ve to solenoid low voltage +ve terminal (with key in ignition in On position)