I've got a radial mains circuit on a 20A MCB. I want to add some more sockets upstairs but can't break into the upstairs ring (on a 32A MCB), can I add the extra sockets on another radial circuit on the same 20A MCB? Or do I put in a fused spur off the existing radial circuit? Or do I create a second upstairs ring off the existing 32A MCB?