@ SM.
You are trying to get an audience about this even when you have been proven to be economical with the facts. (See the Ash thread in R&N)
No Airline has submitted a case for flying in the high concentration ash, but have for flight in the lower concentration areas.
See this CAA document
CAA issues update on Volcanic Ash Arrangements | CAA Newsroom | CAA
Where they say 'many airlines have submitted cases'
Nobody has submitted a case for high concentrations because they cannot prove it is safe to do so.
Stop exaggerating the case.