@Phil Starr I think I can source all of the drivers, preliminary budget looks to be around $600 (about 475 pounds? - I can’t find that symbol on my iPad keyboard). The only problem is the horn, I think ebay showed a seller who ships across the pond. I’m going to have to hunt for a poplar plywood alternative, a cursory search is not turning anything up near by. I’m not in a hurry - I’m a school band director and have access to a couple of amps at work.
I’m most interested in the 8” cab build at the moment though. That one will probably be cheap enough I can sneak those purchases past the budget committee. If I don’t buy music related gear in large sums, she doesn’t complain too much.