Firmness
Firm
Type
Pocket Spring
Depth (cm)
29
Number of Layers
6
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.
This mattress suits you if you want natural materials rather than foam. The wool fillings regulate temperature, which means you're less likely to overheat in summer or feel chilly in winter, and the hemp and flax fibres are there for durability rather than show. The three-tier spring system, 10,500 mini springs plus 1,000 Posturfil and 1,000 Cortec Quad Revolution springs, adapts to your body weight and movement, so you get contouring without the sink of memory foam. It conforms to BS7177: 2008 for home use and Harrison Spinks is a National Bed Federation Approved Brand. Yes, it costs more than most entry-level pocket sprung options, but the spring count, natural fillings and UK handcrafting go some way to justifying it.
Key Features & what's inside
- Comfort fillings. Layers of plush British wool sit at the top, which means natural temperature regulation. You should feel cosy in winter and cooler in summer.
- Comfort fillings blend. Cotton and wool fibres are blended with hemp and flax. These tougher plant fibres help the comfort layers keep their shape over time.
- Ecotex layer. A layer of Ecotex fibres made from recycled materials. It adds strength and durability rather than a feel you'd notice directly.
- Mini Pocket Springs. Layers of 10,500 mini springs contour to your body. Because each spring moves independently, the surface adapts to your shape for a more personalised feel.
- Posturfil springs. An additional 1,000 Posturfil springs respond to your movements and how your weight is distributed. In practice, this means flexible support that adjusts as you change position.
- Cortec Quad Revolution springs. The base layer of 1,000 Cortec Quad Revolution springs adapts to your body for deeper support. Each one has a mini spring inside it, so you get two stages of response from a single spring.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
If you genuinely want a firm mattress, be careful: despite the name, this specific model is listed with a soft to medium feel. Heavier sleepers who need a firmer surface may find it too yielding. It's also a poor fit for tight budgets, with prices starting at £1,199, and anyone wanting fast delivery may find the timescale slow.
Harrison Spinks Platinum 12500 Pocket Mattress (Firmer Feel)
How firm is the Harrison Spinks Platinum 12500?
Despite 'Firmer Feel' appearing in the product name, the MattressOnline listing rates this version as a soft to medium feel. The model is also listed as available in medium and firm versions, so check you're ordering the tension you actually want before you buy.
How many springs does the Platinum 12500 have?
12,500 in total, split across three layers: 10,500 mini pocket springs for contouring, 1,000 Posturfil springs that respond to your movement and weight, and 1,000 Cortec Quad Revolution springs at the base, each with a mini spring inside it for two-stage support.
Does the Harrison Spinks Platinum 12500 come with a trial and guarantee?
MattressOnline lists a 100-night trial with this mattress, though that's the retailer's own offer rather than a Harrison Spinks promise, so terms may differ elsewhere. The listing also shows a 5-year guarantee.
What is the Harrison Spinks Platinum 12500 made of?
Natural and recycled materials throughout the comfort layers: British wool, cotton, hemp and flax, plus an Ecotex layer made from recycled fibres. Beneath that sit three layers of pocket springs. The mattress is 29cm deep and handcrafted in the UK.
How much does the Harrison Spinks Platinum 12500 cost?
Prices range from £1,199 to £2,299 depending on size, with five sizes available from UK Single up to UK Super King. It's a premium price, although the 12,500-spring construction and natural fillings help explain where the money goes.
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