 They were constructed on top of earlier gun emplacements, of which earthwork traces can still be seen in the form of a broad bank running north-east from the castle towards the depot.A further four shell stores were built further to the north, together with other munitions stores, several of which remain.The Depot compound continued in Ministry of Defence hands until 2014, after which the area was due to be redeveloped as housing (with the surviving military buildings refurbished for light industrial use).