We visited Chessington Thurs-Fri staying in the Giraffe room at the resort hotel for the night. Both days were loads of fun with hardly any queues either day and plenty to do despite a bit of bad weather on the second day.
We visited with our 8 month old expecting not to be able to do a lot because of height/age restrictions, but instead we filled 2 whole days up with activities and still could have stayed longer! We went on quite a few rides with our little one and were able to take turns jumping on the big ones too. The zoo, especially sea lion show and Amazu, and Sealife were great and the hotel was lovely. We ate in the Zafari grill for dinner and breakfast; both very nice food and great service.
Will definitely be coming back, albeit probably during term time again as other reviews suggest the whole experience might not be as enjoyable when its busy!