Firmness
Type
Open Coil Spring
Depth (cm)
28
Number of Layers
4
Trial Period (nights)
Warranty (years)
5
Price Range
£349 to £599
Best Sleeping Position(s)
Certifications
Assessed from the specification published by MattressNextDay, captured September 2026, and from regular price comparison across our UK retail partners.
Choose this if firm support is your priority. The PostureTech CS springs are designed to respond as you change position through the night, and each spring includes an EdgeGuard high-density foam insert, which strengthens the edges so you can sleep or sit closer to the side without that roll-off feeling. The double-sided design is rarer these days, and it's a genuine plus: turning the mattress regularly spreads the wear across both sleep surfaces. From £349, it sits at the affordable end for a UK-made, NBF-approved mattress. MattressNextDay lists a 5-year guarantee and free next day delivery to mainland UK, although some addresses may incur a small fee.
Key Features & what's inside
- Knitted Cover. A soft knitted cover that's breathable, which means heat can escape rather than build up. It helps keep you at an even temperature through the night.
- Soft White Fibres. Fibre fillings made from 100% polyester, chosen for recovery and durability. In practice that means the comfort layer springs back rather than flattening quickly.
- PostureTech CS Springs with EdgeGuard. The PostureTech Core Support spring system responds to changes in your sleeping position, targeting support where you need it most. Each spring holds an EdgeGuard high-density foam insert, which strengthens the mattress edges and extends the springs' lifespan.
- PowerPack Core. The PowerPack at the core works with the PostureTech system to keep your lumbar region comfortable and safely aligned. It's the layer doing the deep support work for your lower back.
Layer details from mattressnextday.co.uk product page, September 2026.
Who's it NOT for?
This is rated Extra Firm, so it's not the one if you like a plush, cushioned surface. Lighter side sleepers in particular may find it too unyielding on the hips and shoulders. And because it's double-sided and needs turning regularly, it's less practical if you can't manage flipping a mattress.
Sealy Ortho Plus Bronze Mattress
Across owner reviews on MattressNextDay, customers praise its orthopaedic support and suitability for back pain sufferers, along with the firm feel and the durability of the double-sided design. It holds a 4.7 rating from 56 reviews on that listing.
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How firm is the Sealy Ortho Plus Bronze mattress?
It's rated Extra Firm. That suits people who want strong orthopaedic support, particularly back sleepers and those with back pain, although lighter side sleepers may find it a little too hard at the shoulders and hips.
Does the Sealy Ortho Plus Bronze need turning?
Yes. It's double-sided, with fillings on both faces, so you should turn it regularly. That's slightly more effort than a no-turn mattress, but it spreads the wear across both surfaces and helps it last.
What guarantee comes with the Sealy Ortho Plus Bronze?
MattressNextDay lists a 5-year guarantee on its product page. Terms can differ between retailers, so it's sensible to confirm the guarantee with whichever shop you buy from.
What sizes does the Sealy Ortho Plus Bronze come in?
Five UK sizes: Single, Small Double, Double, King and Super King. Prices range from £349 to £599 depending on the size you choose.
How deep is the Sealy Ortho Plus Bronze mattress?
It's 28cm deep. Standard fitted sheets should work fine at this depth, though it's worth checking your existing bedding if your sheets run shallow.
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