Hi, I'm looking to get a bed for a spare room. I want a single that can be converted into a double for guests. It would be for an adult, but would live in a nursery so potentially some kind of daybed or a single bed with another that slots underneath could be good. Can anyone recommend one that they have slept on that is comfy please, and hopefully not mega expensive? I've slept on the Ikea Hemnes daybed but it gave me a bad back. Thanks if you can help!