Right. Got somewhere - but not sure how. I ran through bothe the latest ideas posted above from Rikki and Andrew, but I'm afraid neither thing worked.

BUT as I was busy copying down images to post I suddenly noticed a different option had opened up in the BiaB ASIO drivers dialogue box (ie the 2nd image in Andrew's post) that wasnt there before.

On the right hand side, under "output drivers port" the new option is:
(2.3) HD audio output 1 + HD audio output 2.

Once I selected that, everything worked fine. But I couldnt figure out what had happened to open that option. In the interests of science and all that, I played around with things to lose that 2nd option - I think by going back to MME setting, and then tried to figure out what prompts it. BUT I'm afraid I cant figure that out. Somehow that option appears, and when it's selected everything works fine. With midi yoke, without it, with various other settings - its all suddenly lovely.

Sorry I cant be more precise, cos it might help someone else. If I figure out any more I'll come back to this thread and post again.

I tried posting pics but it wouldnt happen.

thanks to Rikki and all for the advice,
Cheers Tom