But even if you got a Special VFR clearance would you then be ‘a VFR operating on a Special VFR clearance’ or ‘IFR operating on a Special VFR clearance?
Well, the only real answer I can give is that I don't know for a fact. BUT, what I can tell you, is that this is exactly how VFR at night is conducted in Ireland, where I am based.
In Ireland, there is no VFR at night. Also (unlike the UK) you need an instrument rating to fly IFR, even if you are flying in visual meteorological conditions. This effectively means no night flying for non-IR holders. However, people do still fly at night with a CTR, under Special VFR. It's non particularly useful, because you don't actually go anywhere (you must remain within the CTR to have SVFR), but it certainly is used to get around the no VFR at night.
This is apparently how the authorities intended it to operate, rather than a loophole.