According to Sturtivant and Page's 'Royal Navy Aircraft Serials and Units 1911-1919', Air-Britain 1992, page 298. N9111 is a Short 184: Delivered to 1(S)MAD at Hamble 9 Jan 1919, then at 210 TDS Calshot (Just a bit further south down Southampton Water from Hamble) from16 Jan 1919 to about 30 Jan 1919. It was also tested at Westgate 10 July 1919. So RAF just post-war. It looks a bit like Calshot.