British tank stowage item identification

[Jakko Westerbeke]

I keep thinking it’s a thing to carry other things. None of the ones you see in photos are ever rolled up all the way, they all hang in a curve with the padded (?) side towards the vehicle. That makes me think it’s meant for something to be strapped between the panels — but what? And why would it need that thick panel on the side against the tank if it’s just a carrier for, say, a rolled-up tent? Not to mention that I haven’t so far found a photo of what seems to be this item with something being carried in it.

A folding stretcher does seem plausible, but I for the life of me can’t figure out how to research one of those in such a way that I actually find out about British Second World War ones.