From The West Wiltshire District Guide 1978:
Cley Hill
Between Warminster and Corsley lies Cley Hill, presented to the Nastional Trust by the Marquess of Bath, which dominates the surrounding countryside. It is reputed to be the “iglea” where it is recorded that Alfred the Great encamped before vanquishing the Danes at the Battle of Ethandun.
It is accessible by a track from the main A362 road, and from the top commands superb views on clear days of the greater part of the West Wiltshire district as well as the vista towards the Mendip Hills of Somerset.