mm,
I don't really want to get to deep into specific details as I am really trying to make a much more general point of principle. However, a transit from A to B going straight into circuits at B without an intervening full stop landing would be considered by most to be a single flight, and would seemingly fall foul of these regulations.
Whilst I would not generally have any good reason to operate down to the old 'military reserves', my experience does give me the confidence to decide for myself what is an appropriate minimum fuel for the flight I am undertaking. Sometimes the answer I come up with is more than 30 minutes, sometimes less. I'm sure everyone here can do the same, taking into account their own experience, met conditions, aircraft type, fuel accuracy, alternates and so on. I simply do not think that legislation is wanted or needed here.