I genuinely have forgotten now but I think you're right that milk is still pints. I just think of them as "the little one, the normal one and the big one" which

I genuinely have forgotten now but I think you're right that milk is still pints. I just think of them as "the little one, the normal one and the big one" which I think are 1/2/4 pints respectively. I think where stuff is still normally discussed in pints it's due to that still being the standard measure for retail. For whatever reason milk and beer retained the pint. Also volume of blood in pints weirdly seems to be standard, e.g. when talking about medical stuff informally. The only measure that seems to have gone fully metric in day to day life outside of a few holdouts is temperature.