There is no requirement for holders of UK issued licences to log IFR time.
Art 79:
a flight crew licence issued by the CAA under Part-FCL must keep a personal flying log in which the following information must be recorded:
(d) information about any special conditions under which the flight was conducted, including night flying and instrument flying; and
The requirement specifies Conditions, not Rules.
So long as we have regulations that include unaccountable requirements, we will see all manner of half cock ways of trying to achieve them!
A flight is either IFR or VFR it can't be both, but it can be in VMC in all cases.