Bookworm and Alan M
Agree entirely.
Although it might not strike the reader at first, I would take the statement "IFR flights in Class G airspace being provided with a service by an approach control unit" to refer to Approach Control Service, that being the service, by definition, that is provided by an Approach Control Unit (though advisory by nature outside CAS - qualified in the AIP).
However, if the aircraft is being provided with a radar service - entirely different rules of engagement, this can be either RAS or RIS of course. If RIS, even if the pilot is flying under IFR, this does not require separation from other IFRs (even if the controller knows the flight rules in the first place, which usually he does not). However, this does not preclude the requirement for other aircraft, under RAS, to be separated from the RIS aircraft!