Hong Kong and Macau were leased for 100 years.
Hong Kong was permanently ceded to Britain. It was just the New Territories that were leased. As the lease neared its end, it was apparent that the incredible population growth after 1949 meant without the watershed provided by the New Territories, Hong Kong would not have an assured supply of fresh water to sustain the Crown colony. Britain didn’t bother negotiating an extension to the lease and gave up its claim to the entire colony.
You are correct. See my post 76.