It possibly IS over if the volcano has stopped erupting, and Heathrow hadn't been threatened by any of the forecasts so far, even extrapolating out based on weather charts rather than ash.
You're right though - we need to make sure we have an aircraft available at no-notice to provide the research and evidence needed. Its a shame the airframe that was provided for this task wasn't provided in time and isn't ready yet. Perhaps if airlines, manufacturers and to an extent regulators had spent a bit more of their profits on the required research after the last eruption, rather than apparently forgetting it ever happened, we might have been a bit further forwards.