I did have a ruin with the CSD over an extension seatbelt for my boy.
We flew in CW a couple of days after his 2nd birthday.
He was very small for his age & I asked for one for take-off which wasn't a problem but refused for landing.
He's a fidgety little fella & it's nigh on impossible to tie-in a 2 year old if they don't want to sit still for the amount of time it takes to land at LHR on long hauls.
She said it was against 'elf&safety' to which I pointed out that the existing standard seatbelt did not hold him in any way, shape or form so it was more dangerous from an 'elf&safety' point to leave him like that rather than letting his mother hold him with the extension belt.
She was having none of it because he was 2, even if was by a matter of 48 hours.
The aircon then started dripping water onto my seat which I pointed out was an infraction of 'elf&safety' & that maybe I could be moved to my son's seat & hold him with aid from the extension.
She looked at me as though I'd asked her if was ok to light up a crack pipe.
Most certainly the most curt BA staffer that I've come across on a flight & I assumed that she had no children of her own because they usually bend over backwards for you when travelling with toddlers & babies in my experience & not start quoting the rule book at you.