Just to clarify the RIS/RAS thing and to back-up what Bookworm said, AIP ENR 1-6-1 (Use of Radar in Air Traffic Services) refers. Specifically, 3.1.1(a) of this sections states that for a Radar Advisory Service:
The service will only be provided to flights under IFR irrespective of meteorological conditions;
Point (b) of same states:
Controllers will expect the pilot to accept vectors or level allocations which may require flight in IMC. Pilots not qualified to fly in IMC should accept a RAS only where compliance with ATC advice permits the flight to be continued in VMC;
So while a pilot is not prevented from asking for a RAS while flying under VFR, they would be precluded from receiving it unless IFRs are adopted.