We have two very ancient Soay which we leave with two fleeces on over the winter, just to keep them warm. The second fleece can look pretty tatty by spring, but it does show that Soay don't necessarily self-roo. Yearlings in particular may not drop their fleeces and do have to be shorn. However, as yours have lost their fleece in the important places it sounds as if they will eventually lose it all. The fleece is ready to roo at different times, so the part naked sheep you describe, nice and smart in places, and scruffy and disreputable in others, is fairly typical. If you are desperate to neaten them then you can take the shears to them. The fleece will be well lifted and you can do them at this stage standing up (it sounds as if the difficult bits have rooed themselves). Or you can wait a bit longer to see if the remainder is rooable in say a couple of weeks. Or you can just wait for it all to come off naturally. It helps if they have a post or something to rub against.