Both are pretty decent, mix well, similar specs. I buy a big order maybe once every 3-4 months, I tend to use whatever discount codes I can find on both sites, add the same stuff to a basket and compare the prices before ordering the cheapest. Myprotein is usually a few quid cheaper.
If they're eating or drinking anything low calorie then that would be effort better spent on whole milk + whey. IMO
Compare bulkpowders whey?
I did my nose is all muscley now
This is an OK price but MyProtein quite literally always have a 40% off code floating about. With that, a 2.5kg bag is between £20.99 - £22.80, depending on flavour.