door micro switch white knight CL 447 WV?

2 screws, 2 push-on connectors.

You'll need to get access which will probably involve carefully removing the outer cover(s). Make a not (on paper) of what screws go where and don't over-tighten when you re-assemble.

Here's what you are looking at replacing:

http://www.spares4repairs.co.uk/White%20Knight/Tumble-Dryer/CL447WV/Door%20Microswitch%20Assembly-2879/12/

XXX
June 2016