No good for wall-warts.Recessed mountings for Socket Outlets (and other devices of similar "standard" size) are available in Australia [and in North America]).
My question was "are they not so available in the UK" and, if not, why not?
No good for moulded plugs.
Probably no good for non-moulded if you care about bending radii.
Once again I should have read all the later replies befor posting mine...