would it now be a good idea in light of recent events to have the whole of the uk covered by asu's i.e kent & lincs ?
It's all down to Chief Constables and their budgets (with, obviously, significant input from Police Authorities). As many forces have been caught short by the Gov't pulling central funding for the Pretend Police (PCSOs) - who now have to be paid for entirely by their parent Constabularies - some forces such as Dorset have been actively looking at ways of saving money. Guess which particular assets are seen as instant sources of income should the force choose to dispose of them? Don't go thinking that operational effectiveness wins over beancounting, 'cos it doesn't.
I do agree with you though; having spent many happy shifts in the Kent area on the Air Ambo I don't see how (on operational grounds) the Constabulary there can justify not using a helicopter of their own.