If you are going to have a MOT on the Island in my opinion, you should have the UK one, its not as tough as the N.I test ,and the EU test is very hard, we have a trade body and V.o.s.a in the UK who seem to work hard to keep the test sensible and some of the items that the E.U are trying to implement in the have legal implications in the UK and these items remain an advisory only
It s been said that Garages over charge in the UK they can't really the pricing is set by vosa and the test centres can;t exceed this charge but they do discount to compete, if it was soly government run there would be no discount offered, if your car fails and you don’t agree you can appeal and if the MOT governing body retest the car and finds in your favour the test centre gets points too many points and they are struck off also you are not obliged to have any faults which the test centre have highlighted repaired at that test centre your usual garage can do repairs and probably cheaper,
In my opinion there aren’t enough cars on the Island to warrant an annual roadworthy test and I would think the costs of setting this up would cost millions But hey The I.O.M government are not noted for wasting money in unworkable schemes are they so you will be fine
These are the Current costs of MOT's in the UK