I have a new Aventura 319 with fixed rear bed. My wife and I had problems with sleeping comfortably on the bed and thought it was because the mattress was hard and not a sprung one. Having contacted Swift Leisure about the problem they say that the mattress is a sprung one that is standard throughout their range. Has anyone else with an Abbey experienced the same discomfort with their fixed bed? Has anyone cured the problem and can share their their method? My back would be very appreciated!