it is almost impossible to legally bring them into the EU
Yes. To import such a boat into the EU it will need to comply with the RCD to get a CE mark. You will need to get all the design data to establish which category it will be in, or have it tested. The engine will also need a CE mark, which may be possible if it has had a recent new engine. Other changes to equipment may also be needed. Ignoring the engine the cost of certification can be as much as £8-10k. On top of that you will have to pay freight (or sail it over) and VAT at 20%.Sorry for my ignorance but can you explain that one?