Graham,
The core product is based on the drawings of Cwmgors found in the 'A Pictorial Record of Great Western Architecture' by A. Vaughan. I don't think it is far off West Wycombe. If you have more information, I can sort that out for you.
I'll have kits will me at Kettering (Stand 9) so come and have a look. I'll have Internal Staircase, left and right external staircases options with me. Kits with more options will need to be ordered but I'm intending to see how possible it will be to create a pick and mix parts options via the website.
The kits feature the same 3d printed details as Speech Road, but I have simplified the build process, for example, some of the brackets are half etched to reduce fettling that Speech Road required.
I recommend a dry run and then prime and paint the parts during the build.
Price will be circa £150. As usual though, we replace lost/damaged parts, no questions asked for free.