Firmness
Extra Firm
Type
Pocket Spring
Depth (cm)
26
Number of Layers
2
Trial Period (nights)
100
Warranty (years)
5
Price Range
£395 to £725
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.
If you want proper firmness rather than a mattress that merely calls itself firm, this one is honestly labelled: extra firm, with 1400 pocket springs each encased in cloth pockets, which means the springs respond to your body individually rather than moving as one unit. That helps with motion isolation if you share a bed. The soft white fibre comfort layer takes the edge off the firmness without undermining the support. It conforms to BS7177: 2008 for home use, Rest Assured is a National Bed Federation Approved Brand, and it's handcrafted in the UK. Priced from £395 to £725 depending on size, it's a fair amount of mattress for the money.
Key Features & what's inside
- Comfort Layer. Soft white fibre fillings sit at the surface, which means the extra firm springs beneath don't feel harsh against your body. It's a cosy top rather than a plush one, so expect comfort without much sink.
- Support System. 1400 individual pocket springs, each encased in its own cloth pocket, adapt to your movement and distribute support to each part of your body. This gives firmer, more localised support than an open coil design, and less disturbance from a partner moving about.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
This is an extra firm mattress, so if you sleep on your side, are lightly built, or simply prefer a softer, more cushioned feel, it's unlikely to suit you. There's no memory foam or deep contouring here, just solid spring support with a modest fibre top.
Rest Assured Adleborough 1400 Pocket Ortho Mattress
Across owner reviews on the Mattress Online product page (rated 4.7 from 448 reviews), sleepers report comfortable, supportive nights with a reduction in aches and pains, describing the feel as firm to extra firm with good material quality and durability.
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How firm is the Rest Assured Adleborough 1400?
It's rated Extra Firm, and owner reviews describe it as firm to extra firm in practice. That makes it best for people who want substantial back support and a solid sleeping surface, rather than anyone hoping for a softer, more forgiving feel.
Does the Rest Assured Adleborough 1400 come with a trial?
Mattress Online, the retailer listing this mattress, offers a 100-night trial. That's the retailer's own offer rather than a manufacturer promise, so if you buy elsewhere, check that seller's terms before ordering.
What guarantee does the Adleborough 1400 have?
The Mattress Online listing states a 5 year guarantee. As this appears on a retailer listing rather than the brand's own site, confirm the guarantee terms with your seller at the point of purchase.
How deep is the Adleborough 1400 mattress?
The listing describes it as 25.5cm deep, though its dimensions table gives 25cm with a stated tolerance of plus or minus 2cm. Either way, it's a mid-depth mattress that should work with standard fitted sheets.
What sizes does the Adleborough 1400 come in?
It's available in UK Single, UK Double, UK King and UK Super King, priced from £395 to £725 depending on the size you choose.
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