Air Navigation Order, Schedule 7, Part B (Section 1, Schedule 7, page 13)
Instrument meteorological conditions rating (aeroplanes)
(1) Subject to paragraph (2), within the United Kingdom an instrument meteorological
conditions rating (aeroplanes) entitles the holder of a United Kingdom Private Pilot’s
Licence (Aeroplanes) to fly as pilot in command of an aeroplane without being subject
to the restrictions contained in paragraph (2)(c) or (f) of the privileges of the United
Kingdom Private Pilot’s Licence (Aeroplanes).
(2) The rating does not entitle the holder of the licence to fly:
(a) on a special VFR flight in a control zone in a flight visibility of less than three km;
or
(b) when the aeroplane is taking off or landing at any place if the flight visibility below
cloud is less than 1800 metres.
The question you have given states RVR, whereas the law is written as met vis.
This type of question is terrible, with the negative in there. Far better to ask what you are allowed to do.