If I understand the rules correctly, we are limited to Great Britain/United Kingdom since we just came from Ireland and there is, as far as I can see, no where else to go! So, off we go to the UK/Great Britain with this here 1953 dates three-pence.
Sealand is a self proclaimed principality, 1969, and sits within the British Territorial Waters and is not recognised by any sovereign state. I know it well as I lived in the County of Suffolk for 30 years before moving to Spain. Here is info for members not familiar with their "coinage" https://en.numista.com/catalogue/pieces24527.html I love that piece and will accept it as a valid entry to this thread. GB Sovereign 1967
Germany -> German States -> free city of Lübeck, a member of the Hanseatic League. A 32-schilling piece dated 1797.