So many options.

http://uk.rs-online.com/web/c/automa...sort-order=asc

Id probably consider the ones like this (http://uk.rs-online.com/web/p/limit-switches/0199046/) or similar.

Panasonic, so not cheap crap. NC, Easy to mount, should work for me but I dont really want to buy 6 if I can avoid it.