Harrison Spinks Grassington 5750 Pocket Mattress
Mattress
Harrison Spinks Grassington 5750 Pocket Mattress
Size
Firmness
Medium Firm
Construction
Pocket Spring
Wool
Depth (cm)
28
Layers
2
Layer Details
- Comfort Layer. 100% natural Yorkshire wool blended with cotton, flax and hemp fibres. These wick away moisture and regulate temperature, which means less overheating than you'd get from synthetic fillings.
- Support System. 5,750 pocket springs, a mix of traditional pocket springs and mini springs, each encased in breathable cloth pockets using Harrison Spinks' Cortec Quad Core spring system. Each spring moves independently, so you feel support where your body needs it rather than a uniform push back.
Layer details from mattressonline.co.uk product page, September 2026.
- 90cm each for two sharing: That's a full single bed's width per person, which means a partner who turns over all night becomes far easier to sleep through.
- 5,750 springs across a wider bed: The Cortec Quad Core system supports each sleeper in small, independent zones, so movement on one side barely travels across 180cm of mattress.
- Room for the whole household: When a child pads in at 3am, or the dog treats the bed as routine, the extra 30cm over a UK king is what keeps it workable.
- Natural fillings suit shared warmth: Two bodies generate more heat than one, and the wool, cotton, flax and hemp layer wicks moisture rather than trapping it like foam.
- Fills a large master properly: In a period property or generous new build main bedroom, a UK king can look undersized; at 6ft x 6ft 6in this holds the room.
This size suits you if...
You share the bed every night and want the most space a standard UK size offers, your partner is genuinely restless and distance matters more to you than any comfort layer, or children and pets end up in the bed often enough that a UK king feels crowded. Your bedroom should measure at least 3m x 2.9m for this size to work.
Consider another size if...
Your room is under our suggested 3m x 2.9m minimum, or you'd struggle to rotate a mattress this large and heavy on your own. We'd recommend the UK king instead: 30cm narrower, the same length, and it needs at least 2.7m x 2.9m.
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How much space does each person get on a super king Grassington 5750?
Two people sharing get 90cm each, which is the width of a whole UK single per sleeper. Combined with 5,750 independently moving pocket springs, that distance means one person shifting position rarely disturbs the other. It's the main reason couples with a restless sleeper choose this size over the UK king.
How much bigger is the super king Grassington 5750 than the UK king?
The UK super king is 30cm wider than the UK king, and the two are the same length. That extra width is what makes the difference when children wander in at night or a dog sleeps at the foot of the bed. We suggest at least 3m x 2.9m of room for the UK super king, against 2.7m x 2.9m for the UK king.
Is the Grassington 5750 super king hard to move and rotate?
It will take two people. Harrison Spinks describes this as a heavy mattress even before you scale it to 180 x 200cm, and there's no handle-friendly foam flex to help you fold it round a landing. Check door swings and stair turns before ordering, and plan on rotating it with help rather than alone.
Will the Grassington 5750 sleep cool with two people in a super king?
It should. The comfort layer is Yorkshire wool blended with cotton, flax and hemp, with no foam anywhere in the build, so heat from two sleepers isn't trapped the way it can be in memory foam. The 90cm each of space also helps, since you're less likely to be pressed against a warm partner.
Is a super king worth it for a family that shares the bed?
If children or pets join you regularly, yes, this is the size where that stops being a squeeze. At 6ft x 6ft 6in there's room for a small visitor without anyone hanging off the edge, and the pocket springs keep movement localised. The trade-off is the room it demands: allow at least 3m x 2.9m.