I've been trying to book these all evening but website won't let me. Did you manage to book these this evening and are you using the main link on their website?
@Tommmy We took our daughter when she was five weeks old (possibly younger - it was all a blur back then!) & we had a lovely time! She doesn't remember a thing, of course, but it's a great way to get some tranquility and fresh air!
Kew is lovely at all times of year! Tommmy, it's definitely a good place for a small baby. We've taken our daughter since she was tiny. There are plenty of changing facilities, too.