Also the rules for VFR weather apply to everyone flying in that piece of airspace, no matter what their licence; they must be able to at least have weather that meets the rules for VFR if they want to fly VFR.
Not all licences have the 10km restriction on them. For examply my Irish issued JAA PPL, with no extra ratings, has no such restriction. Therefore I could use SVFR to fly in visibility below that of VFR, in UK airspace.
dp