I have had some and sold them on, because I did not find them particularly well suited to our climate and they had endless foot problems on our soil. Also quite dim and a nightmare to clip... I crossed them with my white Shetland tup, but the only female lamb I got was not very nice (although she did have nice fleece). I just found them too much hassle I am afraid. No shearer would touch them either, so had to hand-shear, and that was difficult as they have the same wrinkly neck as Merinos...
I am still experimenting, but have switched to cross-breeding Gotlands with Shetlands. Actually prefer the Gotland type wool/fleece to the merino type one. (and coloured Shetland ones at that)
A final point, there are millions of merinos in climates better suited to them, so (IMO) not much point trying to develop an really fine wool sheep in a wet climate - my Bowmonts were growing green algae (or something like that) on their backs in a wet winter...