Tall 13 year old - where to buy clothes?

[invicta]

My 13 year old is now 5ft 10", and wears medium men's shirts. Please could anyone advise me where I can get trendy clothes for him. He is not really fashion conscious, and probably goes more by colour than style.

Primark. H&M. Topman.
I have a 12 year old son, and 16 year old niece. She tells me that River Island is cooler than the above for boys, but Ds is happy with them.

My 12yo is about 5ft 7" and is between S/M tops, 28 waist trousers. You have to buy mens clothes

As AuntySib says, Primark, H&M, Blue Inc, etc, etc, etc. Plus the obligatory odd sports-label hoodie, etc.