Car intermittently difficult to get into gear when warmed up

[NickP]

I've been on a couple of long journeys recently and after driving for an hour or so it seems to be more difficult to get into gear. However when the car has cooled down again it seems ok. It's been doing it on and off for about a month now. I took it to mr clutch, the bloke seemed like a bit of a cowboy and said i probably needed my clutch changing. After trying it for himself he concluded that the pedal box & clutch was ok (i mentioned this because i know it's a common fault on polo's). Whilst there he had his hand in the engine and was ragging something about and there was some noise coming from the gearbox area. Miraculously it seems to be ok now. The car is at another garage now and I've asked him to take a look but he is reluctant to start ripping the gearbox to pieces because we can't replicate the fault.

I'm about to drive to South France this weekend so want to get it sorted, does anyone have any ideas??

Many Thanks!