It's not easy is it Slim_Slag?
49(7), as you quoted it starts by saying:
"In this article “specified” in relation to aerodrome operating minima means"
So, the purpose of what follows is to define what they mean by the term "specified", throughout this Article. Nothing more or less.
So the next question is, when do they use the word "specified" in Article 49?
And here is the answer:
an aircraft to which this article applies when
making a descent at an aerodrome to a runway in respect of which there is a notified instrument approach procedure shall not descend from a height of 1000 feet or more above the aerodrome to a height less than 1000 feet above the aerodrome if the relevant runway visual range for that runway is at the time less than the specified minimum for landing.
My bolds. You'll note that specified only applies in this instance to a runway with a notified instrument approach procedure.
And here it is again:
...an aircraft to which this article applies when
making a descent to a runway in respect of which there is a notified instrument approach procedure shall not:
(a) continue an approach to landing on such a runway by flying below the relevant specified decision height; or
(b) descend below the relevant specified minimum descent height;
unless in either case from such height the specified visual reference for landing is
established and is maintained.
Once again, my bolds. Once again, "specified" only applies to a runway with a notified procedure. And that's it. Two "specifieds" to which 49(7) applies, neither of which relate to making unpublished approaches.
I hope that clears it up.
So far as published approaches with un-notified minima are concerned, this is not nearly as rare as you might imagine. You won't find minima as such in the UK AIP charts. You get OCHs and OCAs from which you are required to apply maths to determine your minima. Jepp and Aerad do this for you (to a point). Some other countries take a similar stance, by publishing the constraints, leaving it for the aircraft operator to determine the minima which apply to his flight.
So far though, still nothing to convince me that you have found a law prohibiting descent below MSA other than on a published approach, but I am open to offers.
2D