Got to add my penn'orth to the South Wiltshire cause. As mentioned earlier by Aeshna5, we're blessed with chalk downs including the famous Porton Down which has a preposterous collection of butterflies (plus rabbits, ants and moles etc...); shed loads of buzzards all round the place (I nearly ran one over yesterday as it stubbornly picked at a roadkill); we have pristine chalk streams; we're only a short trip from Cranborne Chase and Dorset and its wildlife delights; half an hour from the South Coast and Poole etc; and a few miles from the incomparable New Forest.
Not truly 'wild', but we also now have our own indigenous monsters back, in the form of the Great Bustards on Salisbury Plain.
Would suit me perfectly if we only had a few mountains knocking around...