Just a word about Wisley. We took our toddler last weekend and it was a bit of a disaster. It's not very family friendly. By 12 noon, all cafes were full and the couple of highchairs in each had people queuing for them. The signposting isn't great either which is frustrating with small people in tow when you end up walking round in circles! Finally you can't walk on the grass there which is tricky trying to explain to a defiant one year old.
Yes, the gardens are lovely but with kids Kew Gardens gets my vote every time. It's brilliantly laid out and even when it's busy you feel like you have masses of space all to yourself. Plus the cafes are well placed and never seem to get crammed to capacity.
And of course it's probably the most beautiful Botanical garden in the world and it's on our doorstep.
Hope that's useful! Happy Bank Holiday everyone.