jmm
You are mixing up two topics of the same general subject - a variation of the Class D VFR minima in the UK (as highlighted by the OP) and the common practice of ATC imposing a level restriction to VFR flights in Class D airspace. As regards the UK's imminent reversion to its pre-EU practice of permitting low-speed VFR flights to fly clear of cloud rather than 1,000ft below cloud, this is perfectly reasonable and practical as it avoids them being obliged to fly at low level for no good reason and we are not in the habit of descending IFR flights on top of them whatever the current rules may be! As regards VFR versus VFR, there is still the in-flight visibility requirement plus, commonly, specific routeings to minimise conflictions.
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