Intermittently running Zanussi TC7103w?

I have a Zanussi TC7103w Tumble dryer, sometimes it fails to rotate when pressing the START button, but if you open the door and rotate the drum and press START it will then run, someone thinks its the thermostat whereas someone else thinsk the capacitor may be at fault, please make suggestions! I have not stripped the panels off so am unsure of the component locations, suggestions appreciated. Thank you