So MN got a mention in this article:
https://www.theguardian.com/lifeandstyle/2023/aug/01/i-dont-come-here-to-enjoy-other-peoples-children-should-pubs-and-restaurants-be-kid-free-zones?CMP=ShareiOSAppp_Other
Which side of the debate are you on?
Personally, after numerous incidents of reasonably rare visits to my local village pub being ruined by parents unwilling to do any parenting I was overjoyed when they banned children under 15 (including the beer garden).
One memorable occasion where the beer garden was utterly dominated by one family of 5 whose children screamed, ran around like headless chickens, knocking over drinks and whose headphone wearing parents barely looked up from their phones until being outraged when told by the landlord to leave.
That said it's also a shame I think having had some fond memories in the past of sitting in a pub garden when the children were small (well behaved/parented and taken home as soon as it was obvious they'd had enough).
Ultimately I think its sad that a few parents seem to ruin it for everyone and allow their children to run riot, but also that it's not inappropriate for some pubs/restaurants to cater exclusively for adults/older children.