Quote Originally Posted by MacMillan of Rathdown View Post
Post-nominals, such as OBE, MBE, GCMG, etc. are not used as part of the signature.

The usual form would be:

(signed) Peter Peel

(printed on a card or letter paper) Peter Peel, OBE
(if in the armed forces then) General Sir Peter Peel, GCHG
(if the son of a Peer then) Hon. Peter Peel, CBE
Ah-ha. I knew you'd have the answer.