Bookworm:
It would not be legal to continue, however you got on to the procedure. NCO.OP.210(e) forbids it.
...which is why your cherry picking of the rule permitting 'descent in IMC below safety altitude for the purpose of landing' without the need to be established on an approved procedure is such patent cobblers. If it were permitted to carry out home-made approaches there would be no reason that you could not start out on an approved procedure and at some point lower down decide 'I'm going to work to my own made-up minima from here on, and it will be legal because I intend to land'.
ShyTorque
Oggers, read the AAIB report. It's not my opinion - it's there in black and white (actually, black and pink in the report, for the more argumentative ones among us)!
Safety Recommendation 2014-35
It is recommended that the Civil Aviation Authority review the regulations that permit a helicopter engaged in public transport operations to descend below MSA for the purpose of landing, when flying in instrument meteorological conditions but not on a published approach procedure.
Well, we are actually discussing what is legal for GA not public transport, and that recommendation pre-dates the publication of both the latest ANO and Part-NCO by
2 years. Anyway, here is the CAA guidance you remain in denial of:
User-defined approaches can be dangerous and are not authorised