Sofabeds - do mattress toppers for them exist?

[CookiecutterShark]

We have a sofa bed which isn't awful to sleep on as long as it's only for a couple of nights, but has such a thin mattress (it's a metal action, trampoline style bed) that it's not comfy for any longer.

I have someone coming to stay who will have to sleep on it for a week and I want her to be as comfy as possible. I've been having a look at mattress toppers, but don't seem to be able to find any to fit a sofabed (170 x 115 cm). I want one which doesn't need to roll away in the sofabed (I can keep it in the cupboard upstairs) but is really comfy. I don't want a whole extra mattress to add to it - though I may do this if needs be... Does such a mattress topper even exist?!

Thanks

I would add a hollow fibre duvet under a couple of sheets as long as it's hypo allergenic (so not too hot). Seems a waste of money buying a mattress topper but a duvet is something you either may have spare already or can always use again.

Yes, you're right. It's a bit pointless if a spare duvet will do the trick. Might buy a new one for the week then 'steal' it for our bed - everybody wins

New sofa bed mattress has creases when opened and isn't comfortable. Thought memory foam topper (140cms) would be the answer but how to store when the sofa bed is in sofa position which is most of the time. Live in small apartment. Is it possible to get it back in the box for storage? Thanks to anyone out there.