Your child's Rugby Boots should fit snugly but not be too tight.
Make sure there is enough room in the toe box for their toes to move around comfortably, and that the heel is securely in place.
Rugby boots are usually sized smaller than school shoes.
For example, if your child's school shoes are size UK 6, go for the rugby boots in size UK 7.
It's also a good idea to try on boots with the socks your child will be wearing during games.
And don't forget to teach your child how to tighten metal studs before each game, that way, you will not need to keep buying replacement studs :)