Campervan bed / mattress

You could always buy a topper slightly bigger and cut it to size. Electric carving knives work well cutting these. You can also buy it cut to size. Google custom made mattress toppers.

peedee

We own a caravan from the 1980’s, with the front long benches that convert to a double bed, or can be used as singles. We upgraded the foam to sleep quality when we first renovated the van, and rather than slats, put in more solid fold up wood over the under bed storage area. Used this both double and occasionally single for years. Getting a bit more creaky nowadays, so we now supplement our bed with a double foam mattress topper, that has been cut in half so we can still use it double, or on top of the foam as singles for a one night travel stop. Try turning your foam benches upside down as well, as this can sometimes help.

Things to be aware of…..more solid wood, and carrying a topper will have weight implications for your outfit, and you will lose some storage having to carry the topper(s). Just buying a topper might not be the answer, nowadays, new caravans are not always built with quality and comfort in mind, it’s more about what they look like in terms of attracting a buyer. So it might be that your foam isn’t good enough, particularly if you are shall we say not lightweight yourselves. Hope you get things sorted👍

You could get a couple of Baavet wool mattress toppers made to measure.  The founders and owners of Baavet are keen campers (motorhomers) and usually willing to help out and offer knowledgeable advice.