Yes bookworm I agree that part of the regs permits a deviation from published procedures which could be interpreted as permitting a user defined approach all the way from safety altitude to landing. I think it is the only place in the regs where the argument that non-approved approaches are legal has any basis. But the problem is it is contradicted by so much of the other regs and information from the CAA that I have already posted.
One thing that is definitely a red-herring is the notion that a landing site is not subject to the regs pertaining to aerodrome operating minima if it is not a proper airfield. And another red-herring is that ad-hoc descent below safety altitude in IMC is permitted on the basis of SERA 5015. But that one you posted above does on its own merit suggest that an unpublished let-down might be legal for non-complex, non-commercial operations.