The Pretty Things were sort of offcuts from the Rolling Stones, and it sounds to me as if vocalist Phil May modelled himself on Mick Jagger. Rosalyn, an obvious Bo Diddley copy, was their debut single in 1964, reaching No 41 in Britain. It was written by their co-manager Jimmy Duncan and Bill Farley, owner of the studio they used.
In 1973 David Bowie recorded the track for his album Pin Ups. I think it is better than the original.