The number of overseas FIs may be a result of two factors. Firstly, there is a smaller market for them in the US where lots of European FIs used to go to gain experience. Secondly, there appears to have been a growth in European FI schools with no corresponding increase in the FI market. In many countries aeroclub flying is unpaid and operates along very traditional lines. In contrast, the UK offers a larger number of flying schools, an opportunity to perfect the English language, and an opening into the UK job market, making it attractive.
Quite often an upturn in the aviation market in one area is not reflected in other areas.