Aaargh!
Looks like I've been a numpty.
Bought some used road cranks without bothering to think about the chainline they'd need to match up with the rear wheel. D'oh.
Cranks are 46mm, wheel is 42mm.
I can't put the chainring on the inside, because it then hits the frame.
If I move the hub across then I'll have to redish the wheel (and it will no longer be dishless).
I think my only way out is to take my medicine and change the cranks 
Just as well I don't run a bike shop as I'd be rubbish.
