Interesting scenario this!!
Being an AA pilot that R44 asked for.......this is my take on the situation.
During Air Ambulance operations in this country (UK), if the information the crew have
at the time is that life is at risk, or injury has occurred. Then the aircraft commander has the authority to land at an un-surveyed site
without the landowners permission. HOWEVER, and it's a
BIG however, this DOES NOT mean that the landing is exempt from the owners permission rule. After landing the commander should, if possible or if required, attempt to gain permission from the landowner retrospectively.
Unfortunately,in this instance, the cry of 'oi, get orf my land' is a valid one!

If the landowner is unhappy with the fact that you've landed somewhere uninvited, they have the right to ask you to leave, forcebly if neccessary! (i.e Plod).
With regard to getting access to the patient. Most things are allowed, but the intimation is that prior to departure best efforts are made to re-instate any damage done to property. Maybe a bit difficult if you've taken a gurt set of bolt croppers to a chain link fence!!!
In 16 years of flying Air Ambulance operations in Gods own county (I'll leave you to work where that is!). I've never once encountered this problem

. Probably because we don't have too many Billionaires down here!
R44 In answer to your other question. Yes there are a few non-mil AA pilots around. Not too many, mainly due to the nature of work and the fact that the pay tends to be

compared to, say, the N. Sea! But anyway, Good old Lizzie does train the best!

And you're right. It IS one of the best jobs going IMHO
Does ANYBODY know how to fly this thing?