The idea of using shorter cranks is one that I never considered before, I took it as a fixed attribute like frame length. I suppose there is the trouble of finding a suitable chainring with suitable length crank, but definitley worth an investigation. The BB is just standard square taper so should not be too difficult I guess.

Hopefully my saddle adapter pin will arrive in the next day or 2, lets see how that changes things first (i.e. one change at a time).