A couple of possibilities come to mind....
There's probably not a lot of money in importing such small boats into a market that is pretty well served already.
Many of the European, and especially UK mini cruisers are bilge keelers - not required nor popular in North America. Also UK boats are rigged/designed for the generally stronger conditions in the English Channel, which may not translate real well to the many light air regions on this side of the pond.
It is interesting, though, to spend some time leafing through the British sailing mags.. definitely see things you don't see over here - but the same goes for Holland and other regions as well.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)