Paul Chocks, there seems to have been quite a lot of VFR traffic out there this afternoon so if the unit you were in contact with had many calls, your service would be downgraded due workload. Other reasons are that you may have been flying in an area where lots of others were flying and that painted returns on the radar but weren't in contact. You may have been too far from the radar head for a radar service to have been provided. Some units (ie NATS enroute) cannot provide a radar service below FL70 outside controlled airspace.
Now what's the implication?