Just got back from shopping with DSes aged 13, 11 & 8 for school shoes, bags & shirts. It was so difficult & expensive!
DS1 has size 9 feet & is about 175+cm. We managed to get him shoes in Clarks outlet but they were £45 😳 I just hope his feet don't grow again, as he has gained 2 sizes over summer! As for shirts- plain white, short-sleeved- I went to 3 physical shops & exhausted online options before finally nabbing the last 2 packs of age 15-16 in Asda!
Ds2 (11) has uniform already, passed down from his brother & friends. His shoes were a real challenge! He takes a tiny size 3 & is narrower than an E in Clarks- which they do not cater for, but they advise putting insoles in. If we are happy to do that, he also needs slip-on shoes, preferably without velcro. I'd be happy with elastic in the place of laces. They had not one pair of shoes like this. Two more shops later & we are finally happy.
Ds3 was fairly straightforward to cater for (for now!) but he is taller than DS1 at the same age, so I can foresee future problems!
And all in all, I am about £150 poorer!