I've thought all along 2 metres was nowhere near far enough. I had a student in one of my classes before school broke up who would cough loudly and vigorously without covering his mouth. It was clear from that that his aerosol would go a long way.
I watched a really good video about the spread, showing breathing, talking, sneezing, coughing aerosol. It also showed the effect of an open window (reduces the risk quite a lot). I've just looked for it to put on here but can't find it.
I don't even like walking near someone outside. If I have to go out, I cross the road if I see someone coming.