OK, Thanks for the responses!
Location: Currently thinking Oxfordshire, Buckinghamshire general location! Yes my intial thoughts were 120,350,355 etc! and we can all guess the major competitor, however I do think I can offer more in terms of communication, quality, safety, sevice etc. I do agree that the out of hours service is a good idea, however generally associated that with Police, Air Ambulance type operations before, but maybe there is a market for it?
no have not approached anyone yet, this is just an idea!