Old Columns under Modern "Jade Garden" (previously "Hazledean") [????- ]

Whenever I walk pass this spot on Park Road or Robinson Road and look up, I notice these big old columns on the terrace base of modern "Jade Garden". There are both round and square Greek-style doric columns and quite magnificent looking. I am surprised they are so unknown to most people as I could hardly find any information about them online and the Government has never mentioned them in anything. I hope Gwulo readers can give me more information and make this place get the recognition it deserves!