Hypnos Cawthorne Extra Firm Double Mattress
The Hypnos Cawthorne Extra Firm Mattress has 1000 ReActive pocket springs under a wool and polyester comfort layer, which means you get very firm, level support with a little cushioning on top.
- Extra-firm feel for back sleepers
- Edges reinforced with firmer springs
- Wicks away moisture as you sleep
£759
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Hypnos Cawthorne Extra Firm Mattress
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Mattress details
Mattress
Hypnos Cawthorne Extra Firm Mattress
Size
Firmness
Extra Firm
Construction
Pocket Spring
Wool
Depth (cm)
26
Layers
4
Layer Details
Pocket spring core
A core of 1000 ReActive springs, each enclosed in its own fabric pocket. Each spring works independently, so the support follows your body rather than moving as one block.
Dual density eOlus fibre pad
A dual density fibre pad that supports the spring unit and helps spread pressure evenly. That means your weight is shared out across the surface rather than concentrated in one spot.
Wool and polyester comfort layer
A blend of wool and polyester fibres that adds comfort and enhances the firm feel. You get a little cushioning without losing the extra firm character.
Cotton and polyester layer
An absorbent blend of cotton and polyester that wicks moisture away from your body. It helps the surface feel drier through the night.
Layer details from mattressonline.co.uk product page, November 2026.
Key benefits
- Sized for a typical bedroom: We suggest a room of at least 2.6m x 2.8m, which means a UK double fits most main bedrooms without the bed taking over.
- Edges you can use: Firmer outer springs reinforce the edge, so with 67.5cm each, you can sleep near the side of the bed and it should feel secure rather than sloping away.
- Support for each sleeper: Each of the 1000 springs sits in its own fabric pocket and moves independently, which means the support follows each of your bodies rather than shifting as one block.
- Easy to dress: Standard double sheets fit, along with a 200 x 200cm double duvet, so bedding for this mattress is simple to find.
- A firm option for a guest room: For visiting couples, a UK double offers a flat, supportive surface, although guests who prefer a softer bed may find it a little unforgiving.
This size suits you if...
You share the bed with a partner who also likes a very firm, flat surface. Your bedroom meets our suggested minimum of 2.6m x 2.8m, and you'd like space for a bedside table on each side without the bed crowding the room.
Consider another size if...
You both want more personal space than 67.5cm each, and your room can take a bigger bed. We'd recommend the UK king instead, which gives 75cm each; allow at least 2.7m x 2.9m.
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FAQ's
Is the Hypnos Cawthorne Extra Firm UK double big enough for two people?
For most couples, yes. A UK double gives 67.5cm each, and the reinforced edge means you can use the full width with confidence. If either of you sprawls, the UK king gives 7.5cm more each and is 10cm longer, which helps taller sleepers.
What size bedroom do I need for a Hypnos Cawthorne Extra Firm double?
We suggest at least 2.6m x 2.8m for a UK double. Around 3m x 3m is the comfortable norm, and that's what you'll want if you plan bedside tables on both sides plus a wardrobe. In a smaller second bedroom, measure the walkway around the bed before you commit.
Should a couple choose a UK double or UK king Hypnos Cawthorne Extra Firm?
The UK double is 15cm narrower and 10cm shorter than the UK king. Choose the UK double if your room is tight, because we suggest at least 2.7m x 2.9m for a UK king. Go up a size if space allows and you'd value the extra room each.
Is a UK double or UK small double better for one person?
The UK double is 15cm wider than the UK small double, at the same length. A solo sleeper with a dog or cat claiming a corner will appreciate the extra width. If your room is under 2.6m x 2.8m, the UK small double needs at least 2.4m x 2.8m.
What are the Hypnos Cawthorne Extra Firm double dimensions in feet?
The UK double measures 4ft 6in x 6ft 3in, or 135 x 190cm, and the mattress is 26cm deep. That depth matters for fitted sheets, so check that the pocket depth on your double sheets suits a 26cm mattress before you buy.