Well, we fixed it for about 2 minutes. It was the signals fuse, replaced it and tried to put a surge through it (revved it with indicators and brake light on etc) and all seemed fine, then I trundled up the half a mile or so to my uncles house following him, didn't give it any beans, and its gone again
Now I either have to get it recovered home tomorrow and then get the garage to sort it during the service, or try the local bike garage and see if they can find the problem quickly and easily.
Could it be corrosion in the connector blocks causing something to go bang? I couldn't see any bare wires touching the frame around the headstock, or anything under the seat, but I haven't looked under the tank.
My suzuki toolkit didn't have any allen keys in, so I couldn't do much sat at Izi's