TOT
28 day rule is what it says, you can do anything you want on your land for 28 days per calender year ( except motor sport which is 14 days). Therefore you can do as many to's and landings as you want. However this rule is the land connected to the deeds so you cant break up a field into 10 owners for instance.
Having battled with dartmoor National Park for some 17 years and spent a fortune !!!