69morris wrote:
Thanks - I'll get one of those today and see if works!

It might be too late by the time you read this, but a better (well,
possibly cheaper approach) would be to test it, and or temporarily
bypass it (just to check that a new switch is what's required)).

I'm sure the specifics of how to do this have been discussed here
before (Google is your friend).

If not, if you are competetent at operating a multimeter, it shouldn't
take too much working out.