IO's comment reflects a specific interpretation of rule 33 of the ANO (minimum height). Which says broadly IFR flight must be above the MSA and then lists 4 exceptions to this general principle. Exception a) says "Unless it is necessary for the aircraft to do so in order to take off or land".
It does not qualify, as it does in other exceptions to rule 33, any minimum viz, a requirement to be on an approach (published or otherwise), in sight of surface, or anything else. Hence the argument that a flight in cloud, below the MSA while approaching to land at an airport with no approach does not contravene rule 33 of the IFRs
This interpretation is reasonably common and is consistent with operations of which the CAA is no doubt aware. Even more odd is the CAA appears to have considered changing this but declined, and only last year 'had the hood up' on this particular rule to introduce a minimum viz requirement on another one of the exceptions.
The FAA equivalent rule does specifically qualify the landing element as only valid when following a published approach (and you could argue that an N-reg aircraft in the UK would be bound by this stricter interpretation, although I believe the specific FAR is restricted in applicability to US airspace)
However, the interpretation as given is subject to extensive debate if you look in the archives.