Doesn't seem particularly fair on the children. What about the bedtimes of older children who aren't simply going to fall asleep in a pram? Haven't we already established they get bored and fractious after a certain amount of time spent in a pub, which from a child's point of view is not the most exciting place to be. Sat around while adults socialise with each other.
I know times have changed and parents want a bit of freedom too but calling for licencing laws to be relaxed to allow small children in the pub until very late seems more about what suits the parents and their social lives than what is good for 'society' as a whole.