and I am not sure if they were allowed to:Are they licenced as an UK-airline and are allowed to operate international flights from England?
I don't believe there is any legal difference since the mid 1990s. Any EU airline is able to operate in any EU country, and I would imagine that they're classed as EU airlines despite being CI, particularly as they only seem to have received any form of aviation regulation of their own in the Islands recently. All G- registered craft too.