my mums birth certificate has a penny postage stamp on it which is oversigned by the registraar

What Constitutes a Seal. A Seal in this case means any adhesive thing, or distinctive mark, that you may adopt as your Seal, and attach to or define on the instrument.

which, Im sure...reinforces your reservation of rights pertaining to the document(s) or instruments its affixed to, and YOUR seal asserts your authority...

"NO FLAG, NO COUNT RY... those are the rules... I just made up!"

i all ways use stamps , i have also made my own seal

if you hand to a justice a document, with a blank reverse side, he could claim he see's nothing. you apply the stamp on the reverse (blank) and sign/autograph/cancel it in red ink (strike through).

http://legal-dictionary.thefreedictionary.com/seal