Hi. I'm installing sound proofing on a party wall and becuase of the added depth need to extend a socket. Ideally I'd like to replace what's currently flush with surface mounted on the new plaster board so I don't have to lose a back box worth of insulation. Can anyone advise the best way of joining the new T+E onto the existing? It's a radial circuit (if that makes any difference!) so only three cables to worry about.