problems changing gear

[Peter1000]

Hello.
I have a passat estate b3, 2.0 petrol.
Recently I have been having trouble getting the car into gear. The problem is not constant, sometimes it will drive fine, other times it is very hard to engage any gear and the car will creep forward when stationary in first gear with the clutch down. I have beengiven conflicting advice from garages. One told me to replace the master and slave cylinder, another told me to get a new clutch. If it was a worn clutch surely the issue would be constant? Often turning the engine off and on again solves the problem and it will be fine again. Can anyone offer me some advice?
Thanks