I didnt realise how rich some of my friends were until I went to their house. The uniform made us all equals in the classroom

Uniforms have never done that in my experience, because there are plenty of wealth signifiers outside of uniforms kids will still notice (pencil cases, bags, PE trainers, mobile phones etc), and even the uniforms themselves are not worn equally. The rich kids have clean uniforms that get regular replaced each term, the poor ones had dirty and ill fitting hand-me-downs.