Jay-Be and the UK folding bed market
Jay-Be dominates the UK folding bed category to the point where most folding beds sold through mainstream retailers are Jay-Be products. The brand has been making pop-up and folding beds for over a decade, and the build quality on the mid-range and premium models is a step up from the generic imported alternatives. Some retailers sell rebranded folding beds from other makers, but Jay-Be is the safe default and I'd not overthink it. I'd start there and only look elsewhere if Jay-Be doesn't offer the specific size or feature you need.
What makes a good folding bed
The mattress is the weak point on most folding beds because it has to fold with the frame, which limits thickness. A 7-10 cm mattress on a folding bed is standard. Under 7 cm and most adults will feel the frame bars through the mattress by the second hour. The mattress material matters too: a pocket sprung folding bed mattress (Jay-Be makes several) provides noticeably better support than a basic foam slab, and it holds its shape through more guest stays without developing a body dip in the middle.
The frame needs to lock open securely and fold without fighting you. A folding mechanism that jams or requires force to operate becomes a piece of furniture you stop using. Test the fold-and-unfold action if you're buying in-store. It should take under 30 seconds with one person and feel stable in both the open and closed positions.
Legs and castors determine whether the bed rolls smoothly to storage and sits level on the floor when deployed. Locking castors prevent the bed rolling when you're lying on it. Rubber-tipped legs prevent floor scratching. Small details, but they decide whether the bed comes out of the cupboard or stays in it.
Sizes
Singles dominate the folding bed market because the use case is typically one guest at a time. Single folding beds store compactly enough for a standard cupboard or the gap behind a door. Double folding beds exist but they're substantially heavier, harder to fold, and need more storage space. For a couple staying over, two single folding beds side by side is usually more practical than one double, and each one stores independently.
A sofa bed gives you seating during the day. A folding bed gives you nothing when it's stored. It's a piece of kit in a cupboard. If the room needs to function as a living space with seating, a sofa bed makes more sense. If the room is an office or playroom where seating isn't needed, a folding bed typically sleeps better because the mattress is designed for sleeping, not for doubling as a sofa cushion. The folding bed is the better sleep surface. The sofa bed is the better multi-use furniture.
Verdict
Jay-Be for the UK default. Pocket sprung mattress over basic foam. 7 cm minimum mattress thickness for adult use. Test the folding mechanism before buying. Two singles over one double for couples. And store it somewhere you can reach, because a folding bed in the loft behind four boxes is one your guests never see. Guests get whatever's spare, and this is a perfectly good spare.
