hi there,i'm thinking of purchasing one of your pocket sprung double mattresses. however i currently have a bed frame with slats and lots of things stored under the bed so i don't really want a divan as i have nowhere to store all those things and a 4 drawer divan would be impractical. if i were to put mdf over the slats and also bought a topper would this be as comfortable as a divan??also i asked you earlier about your 3 year guarantee on the mattress i'm looking at...and you said if it were looked after properly it was likely to last beyond 3 years. i was under the impression that mattresses lasted about 15 or at least 8 years?? is this not the case?thanks very much ?