Surely you cannot log 'instrument time' when flying in VMC conditions on an IFR flight plan.
Airline pilots do this all the time. Not much weather to worry about at FL300+, normally. But they still file, fly and log IFR.
Look at your logbook. The column says "IFR" not "IMC".
But I agree it's the UK which sort of dilutes the difference between VFR and IFR by allowing people to fly according to Instrument Flight Rules, outside controlled airspace, without a flight plan and without an IR, as long as they stay in VMC. At night, you don't even have the choice between VFR and IFR.