I think this whole situation is being handled in an incredibly inept manner.
Some airlines are going to go bust pretty soon. Cargo is rotting in warehouses... Stranded passengers are going to make huge claims on their insurances.
Nobody seems to be collecting data on where the stuff is and what (if anything) it does to engines. The Met Office quite obviously hasn't got a clue. The CAAs are totally lawyer-bound. And there isn't anybody else.
Somebody is going to have to get a lot more realistic pretty soon... but that's not the "European way" of doing things.
Eventually, airlines will collect some data and threaten legal action against the regulators. Then things will change fast.