replacing start pause button on john lewis tumble dryer JLTDC05?

I have a perfectly good john lewis tumble dryer model JLTDCO5 but the start/pause button has decided to stop working. question: how do I get access to this part, i.e do I need to remove the top of the machine?; what part will I need and is it easy to install. I have limited DIY experience but can get by with good instructions. Any help appreciated.