Hi Compound,
Thank you for your comment.
I actually have a complete BIWO kit for an 'A' Class but don't want to risk ruining it as it obviously has some collectors value. I trawled a well known online auction website and purchased a Bachmann Super D as a donor for the chassis to save a lot of work, but feel that a smaller motor will need fitting as the earlier boiler on the 'A' is, of course, a smaller diameter. As you say the C1 would be a good starting point...Although I was thinking 'Oh! That front end!' myself!
As regards collieries I have done some limited research on the subject and I can recommend 'Walsall's Engine Shed' by Jack Haddock as it details colliery train workings from the Cannock pits in some detail. I believe Walsall Wood Colliery fed into Norton Junction and this was LNWR although Walsall Wood was a Midland station and had a connection to the Midlands Water Orton line at Aldridge. (If that sheds any light your way?)