You are correct that the UK legislation cannot apply to other states licences and I never said that it could. What I did say is that it restricts PPL holders with no IF rating to 10Km vis for a SVFR clearence and therefore (should) restrict any other PPL regardless of state of issue of their licence.
What you are implying is that the UK government is restricting PPL holders issued under their authority but allowing an Irish / French / American etc PPL holder into that same airspace without such a restriction. Not a very satisfactory state of affairs!
Again, I stand by my understanding, that if the privilages and rules of the state in which the flight is being conducted are more restrictive than those of the state of issue of the licence of the pilot conducting that flight then the laws of the land take precedence.
Simply my interpretaion of the situation.