Re:
Hi, from what I can gauge from what is available on the web and collected knowledge, not actual experience of the shop, which is worth its weight in gold. I believe the top range Allins were done in house by Peter Cobb, who was one of the top frame builders of the era, and it appears he had certain trademarks which appeared on his frames from WW2. Below is a real early one, 1951/2 and a number in the low 1000's, as you see its very nice, and has same style top of the stay. As it was a busy shop, the lower range frames must of been bought in, for instance your example without seeing the whole frame looks like a Claud, I'm sure Holdsworth was probably used as well, so at a guess there were the two levels, hand built and bought in. So back to your frame, it has no trademark Peter Cobb touches, but its not a stock frame either, so if I was you I would park the Allin thoughts for the time being, and keep digging, you may come back and prove it is an Allin, who knows. The serial number, if an Allin places around 1958, but the twin crown fork places it late 40's early 50's, therefore if the Allin shop was involved it may of been just adding some of the later extra frame fittings, just a thought. Terry