The site presumably closed pre June 1944 as it does not appear on the Jones Map.
Beatrice Temple diary reports she visited Sevenoaks on Friday 2 Jan 1942 and had "a vain hunt for ATS who have moved to Tunbridge Wells". She visited again 27 July 1942. On 16 June 1943 she has a long talk with Wendy at Sevenoaks and Nov 24 1943 she had lunch with Wendy and Mr Oakie at Sevenoaks. It is thought to have been in a derelict building around the Cinema.
Churchill's Underground Army by John Warwicker
Beatrice Temple diary