https://maps.derbyshire.gov.uk/connect/analyst/?mapcfg=portal
click accept and submit then look around the map for the lanes that are open (and its up to date)
I transferred them from here onto Mapsorse a few years ago as start finish WPs but of course the map dosent give clues to how severe they can be. Maybe best to no go down with a 1150 or 1200 to check them out.
I did my own classification a few years ago with green Blue then RED routes.
If yer all get yer heads together yer could do a new classification of the lanes 2016. I do know me way around and some of them are not easy so maybe dont do them on yer own. I have been upside down and hit stone walls broke me ankle and got stuck. and that was the best day !!! I will share my old info but you will have to be aware they are not up to date regarding them being open ( closed ones usually have nice rectangular signs telling yer so !!!. Also they may have changed severity with some being affect by either floods tractors or even being Tarmaced.
HTHY
MIck