TF0565 : The Mind Boggles Doubtful that this is a telephone exchange as the poles are Power lines not Telephone Lines. Also according to the broadband checker web site the nearest exchange is WASHINGBOROUGH less than 2 miles away which would be too near to need a repeater site in this location. Especially one sitting in the middle of a field with no road access for the engineers (looked on Google map).
Looking on the map and Google it might be something to do with the disused RAF/USAF Hospital at Nocton Hall. Just a guess.