How much we see on radar is down to the positioning of the radar head, trust me we see a great deal more than some of the posts here may suggest. I am able to see large trucks on the M4 and ships in the Bristol Channel , so not seeing traffic at a 1000ft is really not an issue within the published LARS radius. Where there are problems with the siting of the radar head ATC units will provide services not below a certain altitude/level .