Now I'm getting a bit hacked off - Continuity on the circuits, and finnaly started to attck the ring. Cross connect CPC and neutral at the CU and took a reading of 0.85 ohms. Checking for bridges, so cross connect both phase and neutral at CU, and go round the sockets, 0.21, 0.24, 1.74, 0.22, 1.55, ... and on one double socket I get a reading of 0.22, and on the same socket, over 1 ohm. Click the switches and the reading changes a bit, sometimes I can get it down to just over 0.2 ... it's all looking a bit problematic.