Just to clarify the UK ....
Rule One of the ANO (off the top of my head...!)
"A VFR flight made at any time in a Class A Control Zone or in any other Control Zone in IMC or night, in respect of which blah blah blah"
Point here is that SVFR is only in a CTZ. The minima of 1800m/600ft is for fixed wing INBOUNDS to an airport, based on the airport Met. Some airfields have different minima, such as Heathrow does.
Is that of any help?