We went to Kidscape in Croydon a few weeks back and the kids loved it. Not super close though. There's also Apple Tree Cafe for little ones (I would say 3-4 yo max). Airthrill in Catford is back open for bigger kids. Oxygen trampolining at the O2 and also next to Kidscape in Croydon. We went to Diggerland in Rochester (45 mins in car) and both my 2 and 4 yo really enjoyed the soft play there