<I know most cyclists don't think british bikes are worth their weight in dirt>
Really? How do you know that?
You are, however, correct in stating that some old Brit bikes are classic bargains- and the few genuine british-made bikes still available are as good as anything on the market.
If you want a modern 'Clubman' frame, just contact Mercian, Jackson, Argos, Roberts, Woodrup, Steel, etc., etc.,......(true bespoke cycle builders, unlike some of the fashion names, with great marketing.)
they'll do 'em off the peg, or custom.