Please help me find grey cotton trousers for DS (age 4)?

[elsiebear]

I don't want to buy synthetic, teflon coated trousers for DS, who starts school in Sept.

I want cotton (or mostly cotton) pull-on trousers in grey. BHS are out of stock. M & S have ones in black, but with zip flies which would probably be too tricky for DS to manage.

So far, can't find any others. Can anyone help?

www.clothes4boys.co.uk/boys-clothes/product/101476632-1402-aw/

If I can find anything better I'll post it

Sorry didn't realise they were school trousers.
Not sure what the sizes are on this website or if they are any good.
www.eczemaclothing.com/Department/School+Uniform/School+Uniform/C52++School+Trousers.h tm