can anyone point me to any thread where EI or REs ops have been queried with reference to the ability of IAA to supervise?
Can't think of one off-hand. There are big differences between these 2 and ryanair. ryanair is far-flung and widespread, for example, making the task of a small regulator that much harder. Particularly one that is uninterested.
EI would need rather less supervision than ryanair I imagine, as they have a safety culture, whereas ryanair don't. Read the Flight Internation articles (links above) about the benefit to safety of a union.
Also, EI and RE don't regularly threaten to re-register in eastern Europe. It doesn't take a genius to work out exactly what message, when ryanair threaten to do this, is sent to the regulator.