Can you fit a single mattress in a lift up storage divan?

[HelenofToys]

My teenage DS is upgrading his single bed to a double. I would like to keep a spare single mattress for visiting friends. I'm really hoping to go for a divan base rather than a traditional wood frame bed to avoid him shoving millions of dirty socks/sports kit etc underneath it.
I've see the lift up divan beds and not all of them seem to have a central bar. Has anyone got one and do you think a single mattress would fit in the space? Thanks.