BA flew into the Ash cloud VERY CLOSE to it's ejection point and the amount and size of the ash was significant.
NOT the same as we are seeing above us ( or rather NOT seeing )
I happened to have a rostered flight into Halim Airport Jakarta, two days after the BA incident and had a good look at the state of that aircraft. We didn't have any experience in those days about the dangers of flying through volcanic dust but I was sure glad that I wasn't operating on that flight. Nobody saw it either before they flew into it.