Bosch WTA 2000?

Hi there, can someone help me, my tumble dryer does turn but sometimes stops and goes cold instead of heating. I have pressed the red switch at the back and although it seemed to be working intermitently but I can't keep pulling out the dryer and restting the switch. The guy I rang this evening tells me that it'll cost £65 to fix but is it something I can do myself. Any help would be much appreciated.