I asked Richard at Shoehealer about these. He thinks they are likely based on a model called the Tetbury that came in black scotch grain, on the 4537 last. I have two Tricker's on that last. Belgrave first (Herring shoes photo); Mayfair second (my photo). I think this last fits great; I'm a big fan. And BTW, I just purchased a C&J on the 337 last, and the shapes are almost identical.