LOL! The cynic in me thought it had been deliberately worded vaguely so that any Court Cases arising would run and run arguing the toss, thereby ensuring both the Prosecution and Defence would make a tidy sum!!!!
I know you are leg pulling, but seriously I don't think there is ANY point behind such allegedly deliberately crap wording because there is no evidence the CAA have ever prosecuted this. You can find recent prosecution details on their website.
Any minima is according to whether the runway etc is seen by the pilot and in a single crew scenario this cannot ever be enforced anyway.
'... may not fly in Class D under circumstances which require compliance with the instrument flight rules'
actually means
'may not fly IFR in Class D' - under ANY circumstances
What about VFR in Class D?