What part might I need for my White Knight CL447WV tumble drier?

The drum on my White Knight CL447WV won't turn and there is a buzzing sound coming from the timer switch. If you give the drum a push it turns very slowly for a few turns then stops. The belt is intact and tight. I have also changed the motor capacitor but this did not solve it. I'm assuming that the drum would still turn if the timer switch was stuck so can only think of motor brushes but it's only a couple of years old.....aarrgh!!

Any help would be very welcome.