Hi Chris
I used to keep a fleece flock too, which consisted of seven wethers of various breeds and crosses, kept purely for their fleece. I kept them in with the stock tups but away from the ewes, purely for convenience.
As the others have said, worm your sheep on arrival (or ask the breeder to worm them as they go into the trailer. Keep them on hard standing for 24 hours so any dropped worms will fall on bedding which can be burned. Hopefully you will not need to worm them again, but as the others have said, watch them for scouring. Depending on your land though you may well need to give them a flukicide in the autumn - check with other sheep keepers in the area or your vet as to the prevalence of fluke, which has a snail as vector so can be a bit mobile.
For an anti fly strike product, Crovect seems to be the easiest to use (it's a spray) and the most effective. However, don't apply it within three months before shearing as it is by its nature persistant, but will have gone by shearing time from the previous years application. Flies can become active in early May, so watch your sheep carefully, dag them so there is no muck around them and bring them in for a close-up check if you have any doubts at all. Check their tails and under their tails, up between their back legs, over the back at the top of the tail, over the shoulders and down to behind their front legs and on top of their heads - just about everywhere then
) Open the wool right down to the skin when you check. Once they are shorn, spray with Crovect (I do it every 6 weeks until late Sept, or early Oct in a bad fly year)
I don't agree about sheep not needing shelter. They do have lanolin which protects to an extent against the weather, but sheep kept for fleece are likely to have fine coats which could do with some protection against the worst wet. We had a ewe who was a DorsetxPolwarthxRyeland whose fleece went pink in wet winters, from a type of algae. Also, the tips of all fleece will dry out and become harsh when exposed to a northern winter, so although I wouldn't coat the sheep, I would provide them with a field shelter.