Owain wrote:

Anna Kettle wrote:
I'm wondering about buying an electrical box sinker (eg Screwfix
91308) Do they make creating a hole in blockwork for a socket much
simpler or are they a gimmick? In my experience the sides of a hole
are easy enough to make but getting a reasonably flat back to the hole
is the tricky bit.

A squirt of filler/plaster/foam at the back as you push the box in will
sort that.

Owain

There were some posts about these things a few months back and they
didn't seem to come out too well and are messy.
Somebody suggested a large core drill, I can't remember the diameter,
but large enough to encircle a box, then drill out the hole to depth
and knock out the middle.
I got one of these and I still have it should I ever need a large dia
hole.

Kevin