Will they breed in the UK if left outdoors? I don't think they range North of the Loire in France, so maybe they wouldn't have survived here even if the Channel hadn't cut them off.
I believe they used to breeding Suffolk, but the colony has been extinct for decades; need to check in Fitter's 'The Ark in Our Midst', when I can lay my hands on it. I can't always find stuff when I want it, what with dogs & children all over the place.