Regardless as if HK has English as official or not,and perhaps prior to returning to the red chinese, the majority of Hongkonese knowst to me, their English proficiency is far to be true, thus the OP's fluency has gotten my attention. Perhaps his Google translate works better than my Japanese tool!
The last time I visited Hong Kong, their inhabitants couldn't speak an Iota in English or did not understand their English..
My comment was more to do with your observation that his English was good considering he didnt come from the U.S. Not to mention the other 1.4billion people around the world who speak English that dont come from the U.S