LOL, perhaps I'll have a bit of rethink about that then. I had hoped to save a bit of metal on the Z-axis by moving the stepper to the front but I ended up with basically the same amount, the price difference was only a couple of pounds so it wasn't really worth it - and it took an age to re-align everything and put the bolts back in :-). I've come to the conclusion that SolidWorks + Smart Fastners + Flexible Assemblies is not a good combination.