You can make a new lens panel for the Thornton Pickard shutter if needed, I make these quite regularly as I restore TP shutters. Another option is to make a new larger lens board like the one that the TPShutter is screwed to and then use any flange mounted lens/shutter. I've done both with 4 of my cameras, and us TP shutters with brass barrel lenses or early lens/shutters like a 1913 165mm Tessar in a Compur (or similar).
It should be a Half plate camera, I made an adapter to use normal 5x4 DDS with my Houghton Duchess, the DDS + adapter slides in like a book-form plate holder.
I get brass lenses at Flea markets and camera fairs for about £20-£30, usually they are missing the flange but they can be found as well at camera fairs, you need an 8" Rapid Rectilinear (R-R) ideally.
Ian