I am attaching a scan of a cover bearing this mark. Dr Gould's first volume states that it is seen on mail from several ships and suggests that it was a base mark

The addressee are a firm of watchmakers in Rye Sussex. The question arises as to why the word (England) was added. Does this suggest that the sender was abroad at the time and that the mark may have originated at an overseas base?

Maybe posted from one of the Scottish bases?
Jim

Spoken like a true Scot!