Contact Hetchins.com and David Miller. Didn't serial numbers start with H and on the rear dropouts? It could be a Vade Mecum 1 with upgades at a later date.
in 1970 Hetchins serial numbers were prefixed with the first two digits being number 10 the next three digits were sequential to the amount of frames built....I would guesstimate your frame to be 1971 or thereabouts
