I have a 12 month old son and look after him 2 days a week in central London. All the weekday baby stuff seems to be Mum focused. If you want to grab a beer or a coffee and discuss engineering, super hero movies or anything else really. All without getting too drunk and within range of a baby change facility. Possibly this could include the parent and baby screenings of films. Babies can be any age but bear in mind I'll plan events with my one year old in mind, since otherwise the sort of activities/facilities required changes.