Here's a guess, mixed in with some data.
For a number of years Comoy had a pipe called the Peer. It disappeared from the fancy brands list in the latter fifties. In 1960 Comoy lists the Peerage for the first time; it stays listed at least through 1962, probably longer.
A few years later the Comoy factory is shut and Cadogan production consolidation begins across affiliated brands. At some point combined production results in cross-utilization of stamps.
So here's the guess: your may pipe date from that era; the approximate 10-15 years between the onset of the mfg consolidation and the elimination of the brass rondelle...