Polly Model Engineering can supply Peters Castle Class drawings and some castings (be warned the Wheel Castings are undersize and the wrong pattern for a castle).
The drawings though are littered with errors (as i have found out to my cost).
I have spent the last 5 years slowly on and off (more off than on), re drawing the chassis in 3D using Alibre Design.
I’ve also had a lot of the unavailable brackets 3D printed in 316l stainless steel, rather than fabricating as suggested by Peter in his drawings.
Nick