Found the reason why the bridge PUP had stopped working.....
The tiny single strand of ultra fine copper wire had broken off at the solder joint. Soldered it back on today, tap tested and it worked so dropped it back in and sounds all good again. Still need to find a bit more spare time to fine tune the action and have a final crack at the intonation. In the home straight with just some TO touch ups to do in a few places.