[I read that he didn't fly through the Red Zone so just proved that there was no ash present which is what the VAAC model predicted anyway. The CAA have his radar tracks. Also he had no scientific equipment on board to measure anything so was relying on the mark 1 eyeball of his pilots. His post flight inspection was presumably limited to an engineer with a torch checking the aircraft for any signs of ash.
He proved that shutting the airports was a nonsense which was the whole point he wish to prove.
CAA trying to have its cake and eat it