There is an entry in Wiki describing this building, which gives these dates: It was built between 1903 and 1906, and officially opened on July 1, 1907.
Donald C Bowie's 'Captive Surgeon' gives a detailed account of his time at the hospital between 1942 and 1945. During that time he was the Senior Medical Officer, and the hospital cared for Allied POWs.
The British military left the hospital in 1967, and it was used as the first location of the new Island School. There is a description of these times, and some photos on the IS website.