THE British Garrison is to leave just half its major sites to the People's Liberation Army (PLA), sources said yesterday. Only five out of the 11 main installations now used by British Forces Hong Kong will still be operational in 1997, though a sixth may be mothballed to allow the PLA to renew its military role. The Chinese, who will be discussing the future of Hong Kong's defence estate with the British in a sub-group meeting of the Joint Liaison Group (JLG) today, have demanded that all military sites now occupied by the British forces be handed over intact. But the British plan is to keep only the Prince of Wales Barracks as the Forces headquarters; the Royal Navy base on Stonecutters Island; the Royal Air Force base at Sek Kong; Osborn Barracks; and either Gallipoli Lines or Cassino Lines for the merged Gurkha battalion. Stanley Fort is to be closed when the Black Watch regiment leaves next year and it is understood that long discussions about the site have taken place in the JLG's defence and public order sub-group. The group, also scheduled to meet on Friday, is trying to reach agreement on the defence estate ahead of a full JLG meeting, predicted to be held in Beijing later this month. The subject has been under discussion for more than seven years. One security source said: ''The whole lengthy, drawn-out affair is a result of the Chinese authorities saying they want everything in 1997 that the British military had in 1984. ''They have been forced to give ground on certain things, but Stanley is one of the ones they really want. ''It may be put to some use between 1994 and 1997, but it will be available to them in 1997.'' Stanley is to be handed over to the Hong Kong Government when the Black Watch leaves next August and it could be used for police training. If handed over to the PLA, it could be used as a base for the Chinese troops on Hong Kong Island, but away from the sensitive Central district where the Prince of Wales Barracks is located. Yesterday, the director of the Joint Services Public Relations Staff, Roger Goodwin, confirmed the Garrison would be cutting the number of major sites. Many of the 24 minor sites, such as the married quarters and St George's School in Kowloon Tong, would also be closed, he said. ''The Prince of Wales Barracks will remain as the headquarters of British Forces until 1997,'' Mr Goodwin said. ''The British Military Hospital will reduce substantially. ''Stonecutters will remain the naval base, the ammunition depot and the headquarters of the Hong Kong Military Service Corps. ''Perowne will close following the reduction in the Queen's Gurkha Engineers and one or other of Cassino and Gallipoli Lines will be given up after the amalgamation of the Gurkha battalions.'' He also confirmed that Sek Kong would remain a land forces barracks and the RAF base until 1997. But the future of Stanley Fort after 1997 was a matter for the JLG.