NorthSouth does the rule only apply if buildings, people or animals are within 500ft. So in open country if none of the above no worries. if a house fly round it by 500ft. Soon we will need laser range finders to stay legal!
I do remember many years ago someone was fined for fly over WOD ndb at less than 1500ft and that was before Woodley was so built up. May be it has to be extreme to be fined.
Our group had a problem flying over Stockenchurch once on route to Bournemouth. Someone reported us as low flying, we had held lowish as RAF traffic passed over in bound to Benson once they cleared a climb started as it was a Cardinal 177 looked like a 152 to a ground observer so seemed closer and the prop tips make a lot of side line noise so it looked and sounded like low flying, this is the case we put before the CAA and they dropped it as we acted responsibly. All I would say is if you do have to talk to them get your story and facts straight then practise being interviewed before hand with person playing mister nasty. The CAA some time use retired police officers and they are NOT your friends so be defensive and economic with the truth.