Firmness
Medium Soft
Type
Pocket Spring
Depth (cm)
29
Number of Layers
5
Trial Period (nights)
100
Warranty (years)
5
Price Range
£1,199 to £2,299
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw is the support system. Beneath the comfort layers sit 10,500 mini springs and 1,000 Posturfil springs, with a base of 1,000 Cortec Quad Revolution springs grouped in fours, each with a mini spring inside. In practice that means pressure relief that adjusts to your weight and movement, which side sleepers in particular tend to appreciate. The fillings are natural: British wool for temperature regulation, plus cotton, hemp and flax for durability, and a layer of recycled Ecotex fibres. It conforms to BS7177: 2008 and Harrison Spinks is a National Bed Federation Approved Brand. Buying through Mattress Online gets you a 100-night trial, though that's the retailer's offer rather than the brand's.
Key Features & what's inside
- Comfort Layer. Plush British wool sits at the top, which means natural temperature regulation. Wool wicks moisture, so you stay cosy in winter and cooler in summer.
- Comfort Blend. Cotton and wool fibres are blended with hemp and flax. These tougher plant fibres help the comfort layers keep their shape over time.
- Sustainable Layer. A layer of Ecotex fibres made from recycled materials. It's there for strength and durability rather than softness.
- Support System. 10,500 mini springs contour closely to your body, backed by 1,000 Posturfil springs that flex with your movements and weight distribution. This is where the personalised, cradling feel comes from.
- Spring System. At the base, 1,000 Cortec Quad Revolution springs sit in individual pockets, secured in groups of four, with a mini spring inside each one. That layered spring-within-a-spring design gives progressive support as you sink in.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
This is a soft to medium mattress, so it's not the right pick if you need a firm surface. Heavier sleepers, and back or stomach sleepers who prefer a flatter, more resistant feel, may find it a little too yielding. The £1,199 starting price also puts it out of reach for tighter budgets.
Harrison Spinks Platinum 12500 Pocket Mattress (Soft to Medium Feel)
How many springs does the Harrison Spinks Platinum 12500 have?
12,500 in total. That breaks down as 10,500 mini springs and 1,000 Posturfil springs in the support system, plus 1,000 Cortec Quad Revolution springs at the base, each with a mini spring inside it.
Is the Harrison Spinks Platinum 12500 soft or firm?
It's described as soft to medium. That gently cushioned feel suits most side sleepers and lighter builds, although anyone who prefers a firm mattress should look elsewhere.
Does the Harrison Spinks Platinum 12500 come with a trial?
Mattress Online lists a 100-night trial with this mattress. That's the retailer's own offer rather than a Harrison Spinks policy, so check the terms wherever you buy.
How deep is the Harrison Spinks Platinum 12500?
It's 29cm deep. That's on the deeper side, so check your fitted sheets will stretch to it before it arrives.
What guarantee does the Harrison Spinks Platinum 12500 have?
The Mattress Online listing states a 5 year guarantee. Confirm the guarantee terms with your retailer at the point of purchase, as cover can differ between sellers.
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