Student
The BAA member was right, Lowfield Heath Road is a clearway with no parking allowed, it is quite vigorously enforced. I remember years ago when it wasnt and to be honest it was chaos on a summer weekend. The road is the only route around the southern perimeter, connecting all the crash gates, its vital its kept clear for emergency vehicles. So you need to walk there to view.
If you want to watch movements from the comfort of your car its possible from the next road out on the centreline, not sure of its name but its slightly higher than the airport so you get a good if distant view of the runway.