How many visas do I need to visit Beijing, Macau & Hong Kong and Beijing Uk.

I am a uk passport holder visiting my son who works in Beijing. I have a double entry we are visiting Xiang then flying to Macau then ferry to Hong Kong and flying back to Beijing from Hong Kong. Am I right that I don't need visas for Macau and Hong Kong and that this one is good enough for the two entries to mainland China?