On Monday, 29 August 2016 22:35:27 UTC+1, Pet @ www.gymratz.co.uk ;¬) wrote:
I've never really found an acceptable solution to the annoying gap that
shows above, below or to one side of a socket/switch after plasterboard
wasn't cut just right to line up with the back boxes.

Squirty foam, then sand fill and paint.

As well as plastic surrounds you can also get wood eg
http://www.screwfix.com/p/varilight-...finished/7327J

TLC may have a wider range.