My Hoover Tumble Dryer start button won't stay in!?

Hi,
I have a Hoover HDV6 Tumble Dryer which is situated in our garage. The start button works but when you let go of it the dryer goes off. If i jam the button in then the dryer works fine with the timer and everything working no problem. I have devised an elaborate mechanism for this!...a stick wedged against it with the other end wedged against my car. However, not being able to use my car if my wife wants the tumble dryer on is starting to become slightly annoying! Can anyone advice 1. Is the switch the problem? 2. If so, where can i get a new one? 3. How difficult is it to replace the switch? I'm a heating engineer so i'm fairly used to this type of thing but thought i'd seek out some pro advice if possible.

Many thanks in anticipation of your reply.