Okay
Even allowing for the sterling rate, and the cost of bringing the boat across on a trailer behind your car on the extortionate ferry, its still a lot cheaper. It is down to supply and demand, pure and simple, and people will always look to offlaod their boat coming into the winter to save on the mooring or garage charges. I was very keen to buy this winter but just could not arrange it. I was targeting an orkney coastliner (precursor to the 440) on a snipe trailer, 2004 20 hp Honda with six hours on it (!), all the kit electronically and they guy was selling it for GB 4750, I was later told

that he would have taken GB 4000! That's around 6000 Euro - a similar boat advertised in Cork at the same time - with a far lower specification esp the engine - was being touted at 8750 EUR. Enough said?
Okay you have ot add the price of the ferry, accommodation, subsistence but that can be cheap enough if you plan well in advance. In my own case I know someone in the UK who visits Ireland regularly in his 4WD and would have towed it up to my door after collecting it in wales

!
There are a couple of issues: First customs can stop you on the way in and ask if you have purchased it abroad. Second its buyer beware stuff, not just from the point of there being no / a long way to get satisfaction but also from the point of stolen goods. A lot of small boats go "missing" in the UK, there are several websites that advertise this and checking is essenital IMHO to ensure you do not become an unwitting criminal!
There is no registration system for small boats in Ireland that I know of...
I am told that the price of boats in the Netherlands is even cheaper...