They had an offer on at the local screwfix a few months ago for=20 "rewire packs" - basically a bunch of assorted sockets / switches /=20 back boxes for about =A350.
I've since had two of the light switches start arcing internally, one=20 with about 250W of load, the other with a low energy 11W lamp. I've=20 had this on a one-gang and two-gang.
The cable connections themselves were secure, it was arcing inside the=20 switch mechs at the pivot point of the metal "toggle".
Just thought it was worth mentioning in case any of you had used them=20 (Screwfix have been notified) :-}