I have a feeling Carlton decided to 'Use up most of their stock' of Capella lugs in 1973. In that year, the Super Course, Competition, and International all used the Capella lugs. Note that these lugs don't work for really small frames and you can find instances where the lugs were sheared, badly, with tin snips or whatnot. Capella lugs never again appeared on Worksop carltons, however, they could be special-ordered on Ilkeston (team pro) bicycles. One of those bikes is stored in the TI Raleigh Team Pros Yahoo Group bike database, I think.
I have a theory that in late 1973 or early 1974 Carlton/Worksop decided to 'wrap' their numbering system and started over using 'A' in their bicycle serial numbers. Then sometime in 1974 there was a change of heart and the 'WxNNNN' serial numbers were introduced.
I have noticed that most of the Raleigh Pro's with 'A' serial numbers (mine included) DO NOT have the 'CC' cutouts in the bottom bracket that were advertised in the 1974 catalogues. On the other hand, all 'W' series Raleigh Pro's that I have seen DO have the cutouts. So that's why I believe the 'A' serial numbered bikes were late-1973 or early-1974.
- Don Gillies
San Diego, CA, USA