Old house, new light switch

[Owlz]

I would have thought it was quite obvious for rewire, the guys just moved in , no cpc on the lighting circuit shown in pic, before he spends £s on decorating and getting it all nice,only to be pulled apart, anyway as been said if done with care maybe hardly any mess. If I were doing it, lets say no conduits in wall etc, I would advise mini trunking surface boxes, and then chase cables in at later date when client is ready for more upheaval, room at a time if needs be.

It's actually my friend's house that they've bought, I'm just living with them so I guess it's the best time to rewire if needed.