Wild Camping in the UK is quite difficult to do and remain legal.
Virtually all land is owned by someone, be that privately or otherwise. Most land within a National Park is often privately owned.
Some NPs, Snowdonia and the Lake District, for example, allow wild camping, as does Dartmoor but it really is aimed at small back packing type camping. Rocking up in a 4x4, setting up base camp with a series of awnings and a fire will be frowned upon.
I've seen photos of groups of 3 or 4 4x4s camped out along Strata Florida (for those who don't know it, it's one of the longest Green Lanes in the UK), but they will be:
a: illegally driving off piste since they've parked up someway off the legal right of way and therefore
b: trespassing as they are on private land.
Scotland is probably the best area for wild camping, but again, be sure of your surroundings, again, privately owned estates cover hundreds of acres and make sure you follow the Scottish Wild Camping guidelines.
The best place to get info about what Green Lanes are still legal is GLASS.
Trailwise is only as good as the input from GLASS members (not sure now, but there used to be two versions - one was the original and is run by GLASS (and you need to be a GLASS member to be given log in rights), the other was an off shoot of the original and wasn't checked properly to be sure the tracks listed were still legal).
THE best way to 100% sure is to visit the Council offices for the area you are interested in and view the "Definitive Map". This is held by the Rights of Way officer for the Council and can only be viewed, not borrowed or copies bought. Just take the time to copy info from it into your own notebook, or onto your own maps.
Beware Treadlightly UK - doesn't really help anymore (last news etc... was uploaded in 2015). Although there is some good generalised guidance.
OS maps need to be bought/checked regularly as even BOATS can change status since the map was last updated/printed.
There are some good Council websites, for example, Cumbria's
Hierarchy of Trails. and Derbyshire's
Mapping Portal.
There's a few other Councils who are or have been getting websites organised and making it easier to get correct, up to date info about what can legally be driven.
Beware Wetroads. While it's a pretty good source of info about where fords and water crossings are, it isn't always up to date with legal ROWs to get to those fords. I remember trying a few a couple of years ago, and it was clear that driving to, or through the ford would require straying from the vehicular ROW.
Sorry if all the above seems to put a downer on UK ROWs, but we all need to do our research properly, or risk getting a Section 59 seizure, which I've seen 3 4x4s destroyed by the Authorities for "off roading" where they shouldn't be - and quite rightly so.
Robin hood bay to. Sunderland point.
