I have spun Derbyshire Gritstone and I like it very much. It would make a super aran sweater, hat or gloves, that sort of thing. Yes, finer than many of the other hill breeds - but it is surprising how many of the hill sheep have really usable fleece.
As with any breed, you still need an individual with particularly nice fleece (I've seen even Shetland fleeces I wouldn't want to spin), the sheep needs to have been healthy all year while she's been growing the fleece, and it needs to have been clipped correctly, skirted and stored appropriately.