Sam Farrell wrote:
You could hire a box cutter with an SDS drill and do a proper professional ,
and quicker job. Have a look at
http://www.screwfix.com/app/sfd/cat/...37679&ts=51549 to see the
sort of tool I mean.

You cut it out with the large round attachment then square it off with the
box. For two gang you cut two holes and use a two gang box cutter to square
it off.

I've been using one of thee (on loan from a friend for the last 18
months!) and it's great. BUT the main bulk of the whole is drilling out,
not chiseled out, and consequently it chucks dust everywhere.

Ben