Rank #10 in Best King Size Mattress 2026: 10 Ranked, Four Spec Sheets That Contradict Themselves
Cotswold Extra Firm Memory Foam King Mattress, 30cm
Price and rating as shown on Amazon when we collected them. Both change.
The Cotswold is a 5FT king size memory foam mattress from naturalex, listed at £217.87 with 4.1 out of 5 from 131 ratings. It is the last entry in this guide, at number 10. Of those 131 ratings, 62 are five star and 11 are one star. The listing describes a 30 cm thick, extra firm orthopedic mattress in gel visco memory foam with a Euro Top, support across 7 zones and a grey cover of SoftSensation fabric and 3D honeycomb mesh, vacuum-compressed and rolled into a box.
The finding in this fiche is in the measurements, not the materials. One field reads Size: 150 x 200 cm | 5ft King. Another reads Item Dimensions: 200 x 30 x 150 centimetres. A third is labelled Item Dimensions L x W x Thickness and gives 2L x 0.3W x 1.5Th metres — take those letters literally and the mattress is 30 cm wide and 1.5 m thick, which no king size is. Set against Item Thickness (30 centimetres) and Item Depth (11.8 inch), the 30 is plainly the thickness and the 150 is the width, so the listing carries the right numbers in an order that fights its own label. Measure the space before you buy. Everything on this page comes from the Amazon listing for this mattress, not from any test of our own.
How those 131 ratings break down
An average hides its own shape. This is the spread behind the 4.1 stars.
Specification
Exactly as published on the Amazon listing, field for field.
| Price | £217.87 |
|---|---|
| Rating | 4.1 out of 5, from 131 ratings |
| Size (listing field) | 150 x 200 cm | 5ft King |
| Item Dimensions (as listed) | 200 x 30 x 150 centimetres |
| Item Dimensions L x W x Thickness (as listed) | 2L x 0.3W x 1.5Th metres |
| Item Thickness | 30 Centimetres |
| Item Depth | 11.8 Inch |
| Item Firmness (as listed) | Extra Firm |
What buyers actually say
Quoted from customer reviews on Amazon
Verified purchase“I have bought quite a few mattresses in my time. I prefer a very firm mattress. This one offered excellent value. When it arrived, in a fairly small box I was astounded. I was expecting something much larger. But when unpacked it took its sap and form. Now a month on I can honestly say that this is an amazing product. Extra firm , king-size and extremely comfortable. And at a fifth of the cost for similar products.”
Verified purchase“Brilliant, value for money. I asked for firm and firm I got. Bounces back as soon as you get up like it should. So comfortable. Delivery was so easy, came rolled up in box once I opened it and rolled it out it went straight into shape. No fluffing about. I paid double for a mattress few years ago and nowhere near this quality.”
What it is up against
The rivals it was ranked against in Best King Size Mattress 2026: 10 Ranked, Four Spec Sheets That Contradict Themselves.
Questions people ask
What size is the Cotswold mattress?
The listing's size field says 150 x 200 cm | 5ft King, and the description calls it a 5FT king size mattress, so the Naturalex Cotswold is sold as a standard 5ft king.
How thick is the Cotswold?
The listing gives an Item Thickness of 30 centimetres and describes it as 30cm / 12 INCH high. Its own Item Depth field says 11.8 inch, which is the same 30 cm recorded a second way.
Is the Naturalex Cotswold firm?
Yes — the firmness field says Extra Firm, and the description calls it extra firm orthopedic support across 7 zones, designed to maintain spinal alignment.
What is the Cotswold made of?
The construction field says Gel Visco Memory Foam, and the fill material is listed as Gel Memory Foam, Latex and Viscoelastic Foam, under a cover of Breathable SoftSensation Fabric & 3D Honeycomb Mesh.
Does the Cotswold arrive rolled up?
Yes, the listing says the mattress has been vacuum-compressed, sealed and rolled in a box, and asks you to wait 72 hours after opening before use.
Why is the Cotswold at number 10?
Because its dimension fields disagree: one gives 150 x 200 cm, another 200 x 30 x 150 centimetres, and the third gives 2L x 0.3W x 1.5Th metres. That makes the width impossible to confirm from the listing alone.
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