According to the books four red deer, a stag and three hinds from Warnham Court Park near Horsham in Sussex were introduced to Captain Brocklehurst's estate at Swythamley just north of Leek in the 1930s.
These deer and their progeny broke out of the estate during WWII to form the population based on the area of moorland known as the Roches. They now seem to be based at lower atlitudes and as you say are spreading out.
Warhnam red deer have some of the best heads in the world and even quite young stags can carry huge numbers of points and are very big in the body. although obviously descended from "park" deer I believe that the Warnham reds originated from UK stock.
This is a photo of a couple of the smaller Warnham stags that I took over the fence a few years ago, note the thickness of the necks.
thanks paul,i wondered if they were out of swythamley.there are sum very large beast about up there,i know of a lad who has a seventeen pointer over his mantelpiece from off the roaches.fingers crossed i might have some land around there shortly.