One of these: https://www.ikea.com/gb/en/p/hemnes-day-bed-frame-with-3-drawers-white-9034...
It's served us well for years but we now need the space. It's well-worn but still functions just fine as intended... a day bed that pulls out into a double bed. I'll be dismantling it this weekend and can deliver in the Clapham/Bedford area (at no charge).