That (to me) is the heart of this thread. You weren't happy, and you should tell BA - if you don't say anything, nothing changes and no-one knows you aren't getting the service/product you want - so everyone gets second best.

You may not even get a response (you probably will); your complaint will get amalgamated into the monthly figures. If the figures for screaming children (or warm champagne, or filthy plane interiors or whatever) go up someone will be asked why, and something might be done. That is how big companies work.

I have only seen one child on the LCY-JFK flight and he was so well behaved I wanted to hug the parents and say well done.