I have ryelands but they are a devil to shear! the legs and belly can be a problem. I am lucky my sheeps feet only need doing every three months and I am getting a dab hand with that! I wouldn't recommend anyone going chemical free when it comes to flystrike as it is terrible to see when a sheep is affected.
My friend is a commercial farmer and he has a lovely breed called "easycare", they moult so do not need shearing because of which are a little less prone to flystrike but still require close inspection every day, the easy care is also more footrot resisitant. He also keeps badger face which are very friendly.
I have kept sheep since last year and it has been a huge learning curve, even with my farmer friends and Dan on this forum, being great help. I would say do not go chemical free until you are experienced and ask a sheep farmer to let you follow them around for a bit, it will give you and idea what time and care is involved, including the paperwork!