The airport broke the night-time noise rules for 3 years on the trot which is why the summer overnight ban was put in place regarding business jets when they were rumbled. They did it then because they thought they could get away with it.
The Arab flight was a Bombardier Global 7000 not noted for medical emergency flights from Abu Dhabi, There was a flight from Newcastle with the third flight from Stuttgart. I doubt there is a single medivac flight a week yet three land in 90 minutes during curfew hours.