I was in DIY emporium and spotted a roll of insulation which consisted of a layer of bubble wrap sandwiched between two toughened layers of aluminium foil. I thought that it could go under the cushions to make the bunks a bit softer (the cushions are thin) and should make them warmer as well. So I bought a roll and cut it to go under the Vee berth. There is enough to go under the short side bench, but I'll need another roll if I want to do the quarter berth. It certainly feels warmer to sit on than the hard plywood. It can't do any harm. Easy to cut and a bit of double sided tape holds it in place. I have cut out the hatches, so they can still be lifted.