It seemed quite simple.

Battery flat on Saturday......ok took it out and charged it up.....put it back in ABS pump kicks in [ABS 2]. 

Ok, so far so good, took out relay.......bike doesn't run without the relay....battery ok next day.

Monday......put the relay in, go for a run, park bike, take out ABS relay....gee the ABS pump is running.....so its getting power from some other source....

Electrics on this K are all unmolested, only changes made are the fitting of air horns and they are on the original horn connectors and all good and trailer wiring all done at the rear indicators and connector block.

For the moment my thought is to disconnect the ABS unit until I can get at the problem but this does not look possible.

Question and help needed is what wires should I be looking at or is there a connector I can unplug.

I have seen ABS 1 and 2 make the battery discharge when the electronics are faulty. There are 2 separate power feeds one is switched the other live and fused. The brakes should still work if the power to the unit is switched off or the harness unplugged.
Tosi Tabuki in Japan knows about the ABS 2 and should be able to help.
http://bmwk10075abs1fix.web.fc2.com/

Rick many thanks on that so seems I have got the switched feed disconnected by removing the ABS relay, but the fused supply remains and that's still live even though ignition is off.

Is pulling the fuse an effective short term solution. 

I did know ABS issues can drain the battery but I had thought the relay to be the only possible fault in the link.

The best thing is to unplug the multi pin plug. Apparently under some fault conditions the brakes can play up if you just remove the relay. I am not sure what can happen but I recall Tosi telling me that unplugging it is the right thing to do.

I am going to look at pulling the plug later.

The second supply to the ABS unit is not fused......pump running and I took out all the fuses and the relay and it stayed running so its still got an electrical connection.