VFR, like the analogy
These units rely on approx £60,000+ per month to keep their head above water. Thats a lot of collection cans and begging. I haven't seen the stats yet but I woud suspect there is a ratio of helo's to population below which the Unit could not financilly survive. [Guess: 1 helo/750,000 pop.?].
Over the next few years, the efficiently run charitable end of the operation will keep the healthy units going. Bad admin/accounting/pop ratio will see the end of the others.
What the country needs is either a bigger profile on sponsorship, or similar to the US (ish), a health tax
I'd pay an extra £1 on my community tax for the air ambulance....