I have just stumbled on this website for the first time and I am so impressed I thought I would share it on the blog!
It details all the BOATS (Byways Open to All Traffic) that can be driven off road with your Land Rover in the UK. The map allows you to drill down into an area of your choice, and view the green lanes that can be driven.
I had a close inspection of my local area, and am pleased to report that its pretty accurate. All the lanes that I know are legally drivable in my area are listed, but its probably worth having a good look in your area to check the accuracy of the map.
This is a brilliant resource, and one I will be using when I want to plan green lane trips in other areas of the country.
Here's the link you need: www.bywaymap.com