BRIMNES Daybed frame with 2 drawers IKEA Sofa, single bed, bed for two and storage in one piece of furniture. Two large storage drawers under the bed. Or this one? It has storage underneath but it's white,and the furniture in the office is dark.
For older kids and teenagers who require a bit more space for sleep, the Large Single Bed is ideal - Large Single Bed from Laurette. https://www.nubie.co.uk/childrens-furniture/childrens-beds/laurette-large-single-bed-120-x-200cm