At last i've found some hardpack tracks that are still in good condition. ......and an area that the local farmers have sold off as a wind farm that has a network of unmade but hard pac tracks conecting up all the turbines..
You are lucky, we have a similar area at Burton Wold windfarm, I was recently using one of these tracks which breaks out onto a bridleway, the farmer chased me in his Landrover and blocked my path. After a lengthy (but friendly) discussion he was having none of it and it was a case of 'Get Orf my Land'.
His arguments being if he let me do it others would follow and the next thing there would be a bike club up there. Also it is a conservation area, bit lame imho as permission has been granted for another 10 windmills, how one guy on a bike disturbs the local flora/fauna to the same degree as months of heavy machinery will is beyond me. I since found out one of my friends sons used to run there and was met with the same attitude and told to leave.
But I accept I was in the wrong, it isn't a public right of way, sad though it was a nice little trail which I will miss.