I'm from rochester Kent, I have alot of permission and it is very hard to get and even harder to keep.
You have a difficult task ahead of you finding someone willing to take you on to 'their' permission.
It is a sad fact that many people have had the good will to show someone onto their patch only to find that they come back later without them and have their permission flouted and name used in vain.
Unfortunately you may have to start the same as many of us, go and speak to Land owners and enter your dog/s to Rat first. this is good drills for you and the dog, and the Land owner will apprec