To Old China Hand - a very valid point.
The disturbing curiosity in this case is that a supposedly bona fide airline can operate thus. Problem is that the IOM government have a CAA but only to govern Manx registered aircraft. There are no permanent staff governing airworthiness, operational standards, etc.
This allows the operation to slip through the net quite easily since nobody wants to see services to convenient locations off the Island disappear.
When I fly from an island in the Irish sea, I prefer to see G- or EI- on the tail. Not OK- or EC- or whatever.
OK they all fall under EASA ruling, but I, as an individual, do not know how rigorously legislation is applied in these countries.