It seems to be a question that is often asked but rarely answered. I'm not entirely sure why. Part of it may be due to protecting the identity/location of lanes and partly the difficulty of gaining the information in the first place and then being asked for it, gratis.
There are various 4x4 clubs and the TRF that will be able to help. Alternatively you can go and look at your local councils 'definitive map'.
For Herefordshire the place to start may be
here.
Worcestershire's map is availabe online
here, although I know there are very few 'green lanes' available to use.
Shropshire's map
here. Quite a few BOATS marked just north of Knighton
I'll happily divulge ones local (ish) to me, which isn't a fat lot!
Just north of Clows Top
here.
Just North of Alveley
here.
Hope that gives you a starting point. Perhaps we need a Green Lanes section available/viewable only to subscribers? Just a thought.
Dan
PS. If you do find any good ones then by all means let me know!