I think that the paradox of the OP's question is that it asks for some opposable clarity in the interpretation of an article which has been voluntarily drafted in such a way as to offer none and to leave, instead, some level of discretion to both the airline (policy may change over time) and its staff (which can appreciate every situation).

Like others, I suspect that the OP would have zero chance with the situation highlighted above of two separate flights and a relatively short time left to make your next booking (even if that time would meet MCT had this been a single booking) but whether or not this would be taken into account if the OP had left 2 or 3 or 4 hours between those itineraries and in what way is, as is intended, a matter of discretion that BA's agents will appreciate on a case by case basis.