Didn't someone miss a point here
There is a key reason for two aircraft in this area. The North East ASU have NO air support unit neighbours. They provide mutual aid into Cumbria, Lothian and Borders and North Yorkshire. So when you have two aircraft, management of maintenance schedules ensures you always have an aircraft available. Now when you have one aircraft, when that goes down for a 400 hr for a week you have ........................ errrr ............... no access to any aircraft, as not even your neighbours have one. Now Mr ACPO, how does that equate to having adequate cover from one aircraft. There are no Eurocopter relief aircraft.
There will be times when there no air cover. Now would this have been the same outcome had the glasgow airport bomber decided to drive into Teeside airport instead.
As you say, these same people agreed the business case for a new second EC135 two years ago.