Wasn't a Bluebird caravan was it? I had one in 1968 with that spec.45 years ago just married we lived in an old caravan with a drop down bed like you are talking about, it had a shelf that became the support ,it was very good with a lovely mattress, the caravan also had an enamel solid fuel stove with a chrome water boiler surrounding the flue which heated the water, it was an easy van to live in, i cant understand why that design is not used today ,altho i do see them in american sitcoms,in apartments, great idea in a studio flat or mobile home
ps hope the knee heels quickly