I am wondering how many RL28s were built? I have bought Cariad ( now Varelie) from John Edwards. Which as I understand was the last built before a fire destroyed the moulds. I do not have a sail number.
Up untill the end of 1988 some 220 RL28s had been built. These included charter boats, and a few fixed keel boats. After that date I do not know how many more were built other than yours.
Unfortunatly most boats lost track of their sail numbers when sails were replaced over the years, and I feel that if you wish to have a sail number 221 would be close to the mark, as, I doubt that any were allocated after 1988.