I'm glad you bought that. I almost pulled the trigger, and have been second guessing myself ever since. (It's on the edge of being too small for me, and I have a 1963 Flying Scot frame waiting restoration.)
I first heard about PT Stallard when researching bikes from the Wolverhampton area (where my brother in law hails from). By all accounts, he was one of the driving forces bringing mass start road racing to Britain.