MummyFit is quite an intense workout that you can take baby to (you don't wear them for it). I've also seen Mamas Got Moves which is a baby wearing thing, but I haven't been to it myself
Mamma's got moves is a fun class. You do a little dance choreography whilst baby wearing. You feel a bit like a teenager making up a dance in school but it is fun.
I go to Pilates at elevenelevenstudios they do a mum & baby session on Thursdays x
Depending where you are in Leeds MQT Fitness and Mama & Me Fitness are both brilliant