To answer some of the questions -
The model was printed at Shapeways as I don't have a printer myself. It's quite expensive but I'd never be able to scratch build it out of plastikard or brass.
The first of the bogies printed was in one piece (same as the Y25 bogie I printed) but the 20 bogie was stiffer and it was hard to flex it to get the wheels in so the second bogie was made in 3 parts - the main bogie with the 2 ends printed separately to allow the wheels to be put in easier.
I'm looking to see what the cost would be to get some bodyshells cast in resin as it would (hopefully) be cheaper than betting them printed. I was also thinking about getting a 7mm DRS shell printed in the future as I converted it from this model previously. If there was demand I could make a 7mm version of this original model for sale- the shell would cost about £130