OK but I can only speak for operation in class G airspace.
In the UK, IFR commercial flights can and do operate to/from airfields in class G airspace. There is in fact very little class E airspace, those airfields with sufficient passenger throughput having class D airspace protection. Several of the airfields in class G have their own radar approach control and when an IFR arrival or departure is handled, it is given a radar service; if there is VFR traffic around and it is identified, the workload for controller/pilot is reduced because the VFR traffic then becomes known traffic, thus there is no need to pass unnecessary avoiding action to the IFR traffic. The VFR traffic is normally (at my unit) identified using SSR, and our CAA have told us that when we do this we must tell the pilot he is identified and verify any associated altitude readout from his transponder. He is not provided with radar service, just Flight Information Service in spite of the fact ICAO Doc 4444 does describe the 'Use of radar in the Flight information Service' in Chapter 8 Section 8.11, the UK CAA insist on providing a range of radar services which are not listed in any ICAO document (as far as I know!).