Hi jaykay - obviously I have to jump in here

We are at 1000' in the south of Scotland so conditions are probably fairly similar to yours, although we don't have a large farm. Our sheep live and lamb outdoors. We keep Hebrideans and Soays, but have in the past had Jacobs, Gotlands, Shetlands and a variety of cross-bred fleece specials, large and small. When my OH became very ill a few years ago all the larger sheep went plus the Shetlands, so I could handle them on my own if necessary. I would imagine that you are not looking for something quite as small as Soays, but if you are, don't believe all the tales of them being impossible to catch - ours eat out of our hands and look for treats in our pockets, and can be rounded up by using sheep psychology

except when we are in a real hurry or it is important we get them right then - no chance of catching them in that situation

Soay ewes are about 23-25 kgs, tups maybe 40, depending on how heavy their horns are

Hebrideans are quieter than Soays and we find we can handle them easily, especially when our Jack Russell helps, and with a handling system set up. They are beautiful to have around and the meat is more tasty than you could wish - darker than 'normal' lamb, low fat and tender. They lamb extremely easily - you may have heard of a few problems this lambing on here but the norm is for no losses. They cross well with a larger tup for meat lambs if that is what you want. Ewes weigh about 38-40kgs, tups 50-55. They come mostly in a 2 horned version but a multi-horned type is available for added interest

Shetlands are the ultimate small easy to handle sheep, they are a similar size to Hebs, ewes are usually polled, tups 2 horned, meat almost as delicious, and they have the double advantage of being fairly cheap to buy (but also to sell) and they have absolutely wonderful fleece, in a variety of colours, which can be sold to hand spinners (online and at Woolfest).
If you want a rarer breed, there is also the North Ronaldsay, but hard to get stock, the Castlemilk moorit, Boreray, Manx Loughtan (similar to Hebs but brown and with a single coated fleece - also come in 2 and 4 horned models). Jacobs have these days become quite large so you wouldn't have a weight difference with your Rough Fells.
How about trying just a few of one of the above to see how your chosen breed compares?