Peter Paine is correct Jack's shop was at 46 Stoke Road, Slough, Buckinghamshire. We used to pop in there when were racing at Slough track. This would have been about 1967. I am sure the shop survived well into the 1970's. I always thought he built his own frames. Very popular frame in the late 60's 70's especially around the Hertfordshire and Buckinghamshire areas.
Best wishes and be lucky. Michael Butler Huntingdon UK.