Hi
we are in East Yorkshire but originally from Leeds. I breed Ryeland sheep both white and coloured and they make fab pets / lawnmowers. Very friendly and placid. I did breed Dexter cows for a while but my experience has been that sheep are far easier on the pasture, the fences and the pocket as well as being easy to handle.
I also breed Croad langshan bantams which are another quiet, laid back breed that dont destroy the garden.
I used to work at the rare breeds farm at Temple Newsam many years ago and looked after pigs, milking goats, sheep, cattle horses, turkeys, chickens, ducks and doves. It's changed a bit since then but its not a bad idea to visit and find out about the different rare breeds before you buy.
I have a friend who breeds donkeys and highland cattle which are also good natured grass cutters.
Good luck