Well, 1. Great Britain is the island on which you have Scotland, England and Wales -- I presume you mean the United Kingdom which consists of Scotland, England and Wales as well as Northern Ireland (which is not on Great Britain) but doesn't include the Isle of Man or the Channel Islands
2. The UK is not part of the Eurozone, unlike Greece which is part of the Eurozone
Thank you for clarifying that. I was under the impression that the EU exerted some authority over England, but I guess that’s just not the case.