I did not know of anywhere in Lincomb to go offroading. 
It's a private site owned by a friend of mine. A nice wooded area with plenty of hills and a few bomb holes as well as a very scenic drive round the property (a farm and equestrian centre) including a stretch along the river bank. There is also a rock crawl section that has been made specially.
We use it twice a year for our Land Cruiser Club meets and it is a very nice site.
Ian