In reply to a post by parish:

In reply to a post by MHC:

Disconnect the wires at the new socket - leave attached at the master and try from the front plate.

I was trying to avoid that. Took ages to wire - fat fingers, thin wires - but i've tried it and it solves the problem so, faulty/poor quality socket?

It's one of these from Screwfix

I think you have answered it ... what did you use to wire it with? And also, what wire.cable did you use?

In reply to a post by MHC:

I think you have answered it

You mean because it's a cheap one from Screwfix?

In reply to a post by MHC:

... what did you use to wire it with? And also, what wire.cable did you use?

It's got screw terminals, not IDC, and I just used the existing wire/cable that is built-in to the house - just replaced the original white plastic socket

EDIT Just looked at the Screwfix page again and there is both a master and a slave socket. I bet I've got the master and having two master sockets is what is causing the problem?

How can you tell the difference? This one has a large 1.8µF/250v capacitor

Edited by deleted (Wed 28-Nov-12 22:02:04)

Master sockets have a capacitor, extension sockets don't. See this gallery.

It is also important that you connected T2 to T2 and T5 to T5, and didn't swap them over when you did the socket change.