Geoff,
I have just chated with another birder. This photo (or this photo set) is the first photo record of booby in HK. No photo was taken for the first and second red-footed booby recorded at Victoria Harbour and Aberdeen ... Also no photo records of boobies at Cape D'Aguilar in late 1990s.
So, I guess it could be the first photo record of booby in HK. Hope it doesn't go wrong.
Captain