A vanilla PPL can fly IFR so long as they are in VMC. For example night VMC flights are IFR. So you don't need an IMC/IR to get a RAS nor to fly at night. Outside of controlled airspace all IFR means is that you comply with rules 29 and 30 (minimum height and quadrantal/semi-circular). Obviously a flight plan and position reporting is needed for flights that transit any controlled airspace under IFR.
Have a gander in the ANO.