There are various sections of the ANO that define privileges or restrictions with regard to a geographic area of , The United Kingdom, Channel Islands, and Isle of Man. In addition, I am 99% sure that the CI issued licences and medicals are effectively UK JAA issued. This would tend to confirm that there is a single overarching regulator. As such, it would be remarkably unlikely for the US to take a view that a UK JAA PPL is not issued by the 'country' relevant to the Channel Islands (which must reasonably be the UK)