Sparky came and put the ring main back on the main board. He left the garage on another fuse. He also moved the ring main (with HiFi) to the first position in the fuse box, ahead of the cooker and everything else.
System is a bit cold after being off an hour, but glad to report it seems back to normal - phew!
Ring main before works, clip #2
https://www.dropbox.com/s/8gki4abb11eag ... D.MOV?dl=0
Ring main after works, clip #2
https://www.dropbox.com/s/99s3ln7pxzjzf ... D.MOV?dl=0
I've not given up either. We need some work doing in the next 6 months that might facilitate another spur via a different route. This time I will make sure the direction is correct.
Also, the Sparky is coming back again soon to finish off another piece of work and so I've asked if he can wall mount a box that can directly terminate the extension block without any plug. It still requires a fuse but is nearer the kit so hopefully will be worthwhile. I never learn do I?! :)
After all this, I've got to say that I'm not at all surprised audiophiles get into all this. The improvement in clarify of a spur on a dedicated fuse box was very substantial (in the room, rather than on clips) - the sort of benefit that people spend vast sums on for HiFi equipment. If only I can find a way to equal that gain in musical engagement then I will be very happy.