Harrison Spinks Knaresborough 3750 Pocket Ortho Super King Mattress
The Harrison Spinks Knaresborough 3750 is a firm pocket spring mattress whose springs move independently, which means less motion transfer when a partner shifts in the night.
- Firm feel for back & front sleepers
- Helps keep your spine aligned
- Sizes up to Emperor
£1,385
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Harrison Spinks Knaresborough 3750 Pocket Ortho Mattress
More available sizes
Mattress details
Mattress
Harrison Spinks Knaresborough 3750 Pocket Ortho Mattress
Size
Firmness
Firm
Construction
Pocket Spring
Orthopaedic
Depth (cm)
24
Layers
2
Layer Details
Comfort fillings
Wool, cotton, hemp and soft white fibres, finished with tufted layers, give natural insulation and help regulate temperature. For you, that means a breathable, foam-free top that should feel less clammy than a dense synthetic surface.
Support system
3750 individual pocket springs sit in cloth pockets, so each spring works on its own. This gives more tailored support to each part of your body, with the firm, no-sink feel the mattress is known for.
Layer details from mattressonline.co.uk product page, October 2026.
Key benefits
- 90cm each, every night: With 90cm each for two people sharing, a partner who turns constantly becomes far easier to ignore, and the independent pocket springs reduce what movement does carry across.
- Room for the whole household: When a child pads in at 3am, or a large dog treats the bed as routine, 180cm of width means nobody ends up clinging to an edge.
- Firm support across the full width: The firm ortho-style pocket spring build keeps its no-sink feel edge to edge, so neither sleeper rolls towards the middle on a bed this wide.
- The right scale for a big room: In a period property or a generous master bedroom, a UK king can look undersized; at 6ft x 6ft 6in this fills the space properly.
- 30cm wider than a UK king: The UK super king is 30cm wider than the UK king at the same length, and that extra width is the difference between sharing a bed and sharing a mattress.
This size suits you if...
You share every night and want real separation from a restless partner, you have children or pets who regularly join you and still want your own space, or your bedroom is large enough that anything smaller would look lost. We suggest allowing at least 3m x 2.9m of floor space, so this suits rooms with genuine width to spare and sleepers who want a firm, supportive surface across all of it.
Consider another size if...
Your bedroom falls short of the 3m x 2.9m we suggest for a UK super king, or you'd struggle to get a mattress this size round your landing. We'd recommend the UK king instead, allowing at least 2.7m x 2.9m.
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FAQ's
Is the Knaresborough 3750 super king big enough for a restless partner?
Yes, and it's arguably the best answer to one. At 180 x 200cm you each get 90cm of space, so most of their movement simply happens too far away to wake you. The pocket springs help too, compressing independently rather than transmitting motion across the bed, but at this size distance does most of the work.
What room size do I need for the Knaresborough 3750 in a super king?
We suggest allowing at least 3m x 2.9m, and around 3.5m x 3.2m feels more comfortable, leaving space to walk round both sides and open drawers or wardrobes. Measure the room before ordering, and check door swing and any tight landing turns, since a mattress this size is awkward to manoeuvre upstairs.
Is the super king Knaresborough 3750 a good choice for co-sleeping with children?
It suits it well. With 180cm of width, a child arriving in the night takes a share without pushing either adult to the edge, and the firm surface keeps everyone supported rather than rolling into one dip. The independent pocket springs also mean a small wriggler disturbs you less than on a connected-coil bed.
How much bigger is a super king than a king in this mattress?
The UK super king is 30cm wider than the UK king; both are the same 200cm length. That 30cm sounds modest but is the gap between comfortable and genuinely spacious for two, especially with a firm mattress like this where you feel every centimetre of your own supported space. You'll need a bigger room: we suggest at least 3m x 2.9m.
Where can I buy the Knaresborough 3750 in a UK super king?
Availability is limited, so the simplest route is the live retailer table on this page, where prices are updated as retailers change them. Stock in specific sizes can move separately from the model as a whole, so what's shown here reflects the UK super king rather than the range generally.