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

If you have the jumpers on and you have 10 volts AC going into the bridge but nothing coming out of the bridge the only thing left is the bridge.
have you tried a different bridge?
just check for continuity again from the GND on the bridge to the Gnd else where on the board.
there is nothing else i can suggest now that you have followed Neno's repair guide. 
If you can't find out what is causing the problem send it down and i will sort it out for you.