This ones still a bit of a mystery to me, it was a childrens home up until the late 1960's then with the construction of a nearby very big nuclear submarine base it became incorporated into M.O.D. land. The Marines were planning to make it into a HQ with large training camp in grounds, this never happened. It is steel shuttered up now, inside is pretty much trashed.
This site still is within Ministry of Defence land at present, however is pretty much overlooked by the local MOD police.