I've read 6 pages on this thread now which started as the OP asking if they should complain about how they were spoken to by crew and arriving at what method BA use for restraining unruly passengers.

The OP seems genuine enough and out of consideration for other passengers, took a "grumbling" child somewhere else. At that somewhere else, the OP themselves got grumbled at by crew that obviously thought their quiet was more important than that of the passengers. Truth is here that the OP is "damned if he does" and "damned if he doesn't". Why all this posturing and argument over rules, regulations, industrial agreements and rest periods. Consideration must be given from all sides when in a tiny aluminium tube in the sky. I tolerate loudly chatting cabin crews sometimes on their "break" in the middle of the night and they must tolerate the odd screaming baby, just as the other passengers must. Give and take. Live and let live.