Shelter - a windbreak is fine (eg made with pallets in a noughts and crosses pattern. Make sure its well secured with baler twine and pref also peg it down to the ground with angle iron pegs if you are in exposed/windy location). The sheep will use any shelter or windbreak as a scratching post and can push it over otherwise
Fleece - from my experience to date with a 30 strong herd, while many lose a bit of fleece naturally, none of mine shed enough to not need shearing. Also if you leave it to shed naturally that might be too long from a flystrike point of view. So I would say you should plan to have to shear. But with only a couple/few you could do it by hand using £12 ish hand shears, if you dont want the expense of electric shears.
Breed of ram (tup). To be honest if you are wanting fab flavour and only breeding for you/family/friends I would go for a Shetland ram. It'll cost less, the lambs will be born lovely and small so very low birth problems likelihood (Ive had none in 3 years requiring any intervention!) and the meat is sensational and the joints are ideal for modern family size. My Shetland ram is a real sweety too, not aggressive in any way, gets bullied by the geese! If you do decide to cross, then breed would depend on whether you would need to sell any in the future. ie Cheviot is the traditional cross for Shetland as the ewes from that cross are bought by 'proper' farmers to cross with a commercial breed like Texel. The lambs from that last cross are meaty and the ChevxShet are good mothers but big enough for a commercial sized ram. Or, you could do as my vet does and use a Lleyn ram, this wont be as valuable per lamb but Lleyns are prolific in terms of numbers of lambs and good milky mothers. (just watch tho, multiple births are a risky approach for the unwary, one of the plus points of pure shetlands is very very rarely do you get more than twins, which helps reduce risks a lot for the mums).
Age to slaughter. If not castrated, then unless you can individually segregate then they would need to go quite young. If castrated or females, it's really personal taste but ideally and if you have the ££ for hayto feed them, they would go off at 12 months plus ie keep them over the winter, let them fatten on the spring grass and then send them or even keep them till 18 months or 2 years. That way you get a bit more bulk and size.
£30 seems fine as a price to me, Ive paid £25 but that was for younger ones so allowing for that, not much different. Pretty good deal when you consider the cost of commercial sheep - £100+! Mine arent registered either and we do the same thing, raising mainly for ourselves (tho have an overload of ewe lambs this year so may have to sell a few!)
Hope this helps!!