Anyone been to Kew Gardens recently?

[CDMforever]

Thinking of taking the DCs aged 12, 4 and 2 for a day out at Kew. I love it there, is there much to do for children? On the website it says children are free, is that aged up to 18? Seems generous?!
We live about 2 hours away so it needs to be worth the drive!!

I live very close and love it - there's now a playground area near the Elizabethan cottage which is good, and the palmhouses are great fun for little ones (there are aquariums downstairs in one of them, and the Princess Diana palmhouse is good too). Haven't been for a month or so but it is a good all day outing...