There are two afternoon teas. One is for kids, it's Tea with Alice. Alice and Tweedle Dum/Dee are generally the characters there. You will be shooed away, and not allowed to stay in the room with them.
The other is more of a formal tea, there are no characters. There is a childrens tea on the menu. It's a quiet and refined atmosphere, and frankly I wouldn't take a three year old there. I took my seven year old neice, who is a very quiet and well behaved child for the first time yesterday. A couple of years ago we chose the Alice Tea for her, which was a better choice at that time.
Anne