Where to get smarter trousers for stocky 10 year old boy

[2018name]

Please can anyone tell me where to get smarter trousers to fit a very stocky 10-year-old boy. I can get school trousers to fit and tracksuit bottoms but I cannot seem to get any chinos or similar (smarter trousers) to be able to fit him - If I go just for a bigger size the shape of the hips and length to crutch is just wrong. Has anyone found somewhere buy from? Thanks

I think H&M has a plus-size range for boys.

American brands are your friend here. GAP Ralph Lauren / Tommy Hilfiger.

My friend just buys bigger sizes and then shortens them but turns them up so they can be let down a bit - she found the H&M things are great but always out of stock xx

How smart do they need to be? Next plus size do black jeans?

Can you get school trousers in a different colour e.g. if he wears grey, get him a pair of navy trousers?

Sainsbury’s do plus size for kids online

Next do a plus size children's range IIRC.
Look online.