In a recent message "DCP23" wrote:

http://cjoint.com/?jvrd1QgqRX

This is a British Guiana stamp with an overprint "Marine Detatchment", which
neither Scott nor Stanley Gibbons know nothing about.

I presume you mean neither know anything...

I suspect it is a private overprint used in the manner of perfins.

Is it gummed?

--
Tony Clayton
Coins of the UK : http://www.coinsoftheuk.info
Sent using RISCOS on an Acorn Strong Arm RiscPC
.... A seminar on Time Travel will be held two weeks ago