On Fri, 18 Dec 2015 19:43:41 +0000, Tim Watts wrote:

Yeah - I'll get a new switch of the same make (for same terminal layout)
next time I'm up TLC in a week or two.

Hum, a plain switch running hot when the associated MCB/RCBO is cold.
Bear in mind that MCBs have a thermal part...I think I'd be down the
shops tommorow or not use what ever it is until the switch has been
replaced.

Why is terminal layout so critical? OK 10 mm2 isn't the most bendy
stuff but the switch will be on a 47 mm deep box won't it to give
room. Take a drawing of the layout with you so you can get something
close.

--
Cheers
Dave.