Ah, nice detailed photos of the plaster models. And no, I don't know whose head that is - not mine.

By the way, while Ireland did not issue any coins when the country joined the European Communities in 1973, the Airgead exhibition features this medal. (Sorry for the blurry image, but due to the glass and lighting, several objects were difficult to photograph, at least for me.) The inscription says "TO COMMEMORATE IRELAND'S ACCESSION TO THE EUROPEAN COMMUNITIES", in the center you see three flying birds (swans, I suppose), and the date 1973 is at the bottom. Since at that time Denmark, Ireland and the UK joined the Communities, the birds may represent the three. Just a guess ...
Christian