I've experienced worse in my own house, although not in UK. There was a mixture of aluminium and copper wiring. They don't use twin & earth or ring mains but wiring runs in conduit high up on the wall, with junction boxes above switches and sockets. Every cable join was done by twisting and taping, most of the sockets had no earth wiring. There was not even a consumer unit as such, just a couple of randomly located MCBs, sealed by the electricity supplier (one for cheap rate, one for normal rate). Sometimes I would hear sizzling sounds due to arcing in one of the junction boxes!