Right there are quite a few clubs around you, It depends which one you want to travel to. Newark model car club is closest, unfortunatly they don't do buggy racing and I think they have moved to grantham now.
For buggy racing check out the club section on me-or.co.uk :
http://me-or.co.uk/index.php?option=com_content&view=category&id=40:1 10-off-road-racing&Itemid=54&layout=default
Those are the main buggy racing clubs in the region and there is also another club in mansfield who i believe still race buggies on a wednesday.
We have a couple of guys who come from Lincoln way to race at West bridgford model car club in nottingham.
hth