OK, Followed Nino's guide exactly, replaced all 5 BRs and Caps - although i did not change c4 as i don't have one here at home. Put all his pictured traces in and......

Same thing

Then i put another driver board in, and everything works perfectly - so its definitely a board issue.

I keep thinking its something at the input part of the circuit as when i measure DC volts from GND to the + of BR2, i'm only getting 0.5V - it should be much higher than this - is this the clue to solve this or just a red herring? (even though there is continuity from pins 1 and 2 of 101 to the AC lugs of BR2)

Thanks

Rob