Funnily enough I was at a meeting last night where we discussed this. You 'own' none of it. Someone said he thought it was called the 1922 Churchill Compromise (because Churchill was on this particular committee) and the original idea of Rule 5 was not Low Flying as such but to ensure people could fly where they wanted, with a few exceptions. Over the years more has been added to Rule 5 and it has become the 'Low Flying Rule'.
I have no idea if this is correct. I cannot find anything on the 'net with a search. Be interested if anyone knows more.