Within Europe, it does not matter where the company is based.
After all everyone is operating to JAR-OPS 1 requirements and with the exception of the UK using the same currency.
That is what an open market is all about.
Ryanair is an Irish run European Airline with bases in a number of countries. As long as the aircraft are registered in a European country, there is nothing anyone can say.
If the CAA can't talk to the IAA about any concerns then there is no point in UK operators crying.
FTL abuse is just as rife in the UK. Have a read of "Feedback" to see some of the reports.
DFC