I of course think Castlemilks are beautiful - and can be very friendly if you get the right ones. They're a cracking cross with Shetland, too.
I've heard (on TAS, of course) that North Ronaldsays are very copper intolerant - which is why I won't be bidding for the black ewe at Carlisle tomorrow, much as I absolutely love spinning NR fibre.
Our ground is copper impoverished, but we have licks out for the cattle, which have quite a bit of copper in them. I'd be terrified my NRs would have a lick and their livers explode.
Nothing wrong with Soays, I just haven't had them myself.
Another breed you may consider, being more local(ish) to you is Portland. Lovely tan faces, sweet brown lambs, beautiful beautiful
fleece.