Not much use to you now, but I saw something in a Belgian or Dutch boat magazine. it looked like teaj dekking that hinged in a couple of places to turn into a sun lounger.
I'll check when I'm home this evening if I still have the magazine and send the website or contact details of the manufacturer.
Have you tried a garden centre? Might sound silly but one by me sells a multitude of folding teak things and could have cushions on them. Depends on wha your after.
I have just purchased 2 folding chairs to replace the uncomfortable ones in a bag. They recline and you can also buy a foot rest, take a look here www.towsure.com/category/7044-Saville_Chairs
If you know anyone in the Caravan Club borrow their membership card and get a 5% discount.