Hi, lovely frame, but so many conflicting clues. I just thought I could throw a possible line of inquiry your way, seeing the stamping on the dropout reminded me of my Allin ( early seventies - see below ), the serial number would place it late 1958/ early 1959, which does place it right for early use of centrepull brakes but one of Peter Cobb's trademarks was the almost touching seat stay tops, nearly a wrap around but not quite, but that may of been just been for the Stan Butler Special ( the name given to the top of the range Allin ), worth a look any way. Terry