The joint Police / Amb set-up do a cracking job but a dedicated HEMS aircraft would undoubtedly be a step forward for a number of reasons:
No conflict between HEMS / Police tasking
Dedicated A/C fit
2 Paramedics....etc.....
However, I do agree that getting the South up to 7 days would be a better priority. Just an off the cuff answer though. Maybe they have a reason for moving North.