Back to square one I think. UU put a CAT and Genny on the lead and got a very strong trace down the driveway to the pavement, marked it up and got their contractor out to fit a stop tap, but when they dug down in this location they couldn't find any trace of the water main so have backfilled and made good. I have requested a revisit by the inspector but I doubt this will change anything and I reckon they may refuse to reattempt.
I'm back to considering a live swap of the guts of the stopcock only. Bought an almost identical stop tap and all dimensions seem to be correct to swap the guts only. I would turn on all upstream taps to relieve pressure before unscrewing the old one and screwing in the new.
What do you reckon? Go for it?