This describes those baby groups so well.
Op just don't go to the baby groups. You don't need to go to a single one. Before your baby is about 9m all they want is you. I personally think it's all a hustle when they say these classes improve your baby's speech development etc. You can sing, clap or just talk to your baby. I did one or two and vowed never again, and dd is doing great for speech milestones.
Things I enjoyed:
Before about 4-6m you can pretty much take your baby everywhere you want to go, as long as you can sit comfortably to feed them. I lounged in pubs constantly, either alone or with friends or with DH. I went into town and met my working friends on their lunch break to spend an hour having lunch. I went to town and wandered the nice department stores like fortnum and Mason to do my xmas shopping (although dd weed all over the changing table there, I had to clean it up while she screamed, that was a bad day)
There was also baby cinema (films for grown ups, but you can bring your baby and it's ok if they cry etc).
From 6-12m we did pubs and cafes and family friendly chain restaurants like Pizza Express where DD could try some dough balls or bits of cucumber and tomato. Long walks in the park. The occasional visit to a playground, baby swings. Hours in the playpen in the living room while I watched TV or played games on my phone.
After 12m it was soft plays, and playdates with nursery classmates (on my days off from work).
I'm expecting DC2 soon and have already decided that he will not go to a single baby group session haha