Just one more final update to this one, I went into Peterborough General Hospital on Friday and had a 2nd operation, and this time it was successful!
The surgeon was bloody brilliant, and has managed to remove the main offending stone which was trapped tightly in the tube between kidney and bladder, then he also got to another large stone inside the kidney itself and removed that as well. Honestly, the way they describe it, this might as well be science fiction, with lasers and cameras going into... well... places you would believe possible! He fitted a catheter again due to my previous experience (he'd discussed that with me before the operation went ahead), and that will be removed tomorrow, together with a temporary stent which replaced the previous one he'd fitted. This one is on a "string" - In reality, a tiny thin wire that will get pulled out at the same time as the catheter tube - Ouch!). All very unpleasant, but necessary and at least this time he fitted it while I was unconscious so I didn't feel it going in, which was the worst part on the previous one.
I was going to put this pic on the WRUW thread, but they kept me in overnight and I didn't get home until late last night:
I like the colour of the strap, but the timekeeping on this one is rubbish!
Once again, thanks very much to everyone who took the time to comment here, it was greatly appreciated and cheered me up at quite a difficult time