Continental and Irish/GB fittings are nearly the same . The difference between the standard fittings (pipes and couplings ) is so small that many fitters wouldn't realise that there is difference at all. However there are also adapters available . I installed pressurised taps and pressurised toilet flushes myself imported from the continent as well as my under floor heating system , absolutly no problem at all .When you check the solar panel manufacturers home pages they nearly all provide you with plenty of literature , videos etc. on how to install a solar heating system. You don't have to be a plumber.But I put a bet on it : most plumbers would be happy to assist, a solar panel is a good and free way of advertising a service , you'll get plenty of inquierys from passers by .
But you should be able to " stand hight " when working on a roof , of course. The panels can be heavy , so you need a crane and/ or some helpers and a good scaffolding. All this info you will find in the suppliers manuals , or you get yourself a book , Amazone would have the right ones . Make sure you buy a book made for the EU market , US plumbing and calculations would differ.
Get the necessary information - a step by step guide - before you decide for the panel . Do your maths concerning heat demand and wind stability etc.. The fixtures ( when going for a roof based panel ) are important , when buying them check that they are build to EU standard . That will make the construction insured in case of storm damage . I've seen TV areals and satellite dishes fixed here in a way the health and safety inspector would have days of work just to fine the home owners in one road .
All this is no problem when installing them in the garden for example or on a non-shaded wall or on a flat roof /extension ect..
Check the top 50 solar page mentioned above , you will find plenty of info there. There is also an EU standard for output and safety and so on . Buy only material that confirms with this standard.The easiest method is to buy a full set from one established seller.
Good luck with it, every panel is a sign of peace !