OK chaps, this is now solved
Darren from Berrybrook Morgan offered up the quick release hub he sells and it moves the wheel towards the dash by 10mm.
Not only does it allow me to remove the wheel, it actually puts my new dished wheel back where it was with the original flat one, so it's a win, win
I will need to source an alternative horn arrangement, but as the Moto Lita horn push has always been rather poor in operation, this is actually a good thing.
So perhaps more accurate to call the Berrybrook QR hub a win, win, win
