I ordered a size 8 for my 7 year old grandchild. When it came it looked like it wouldn't fit a 4 year old! I took it to the shop and they let me change it, no questions asked for a size 12 which fitted perfectly!!
No questions asked when I wanted to change it
No warning that I might need a bigger size
Great for use while surfing in Cornwall over the summer.
No issues with getting cold.
Perhaps a bit of chafing, maybe sand?