Harrison Spinks Oasis 5500 Firm Mattress

Assessed from the specification published by Mattress Man, captured September 2026, and from regular price comparison across our UK retail partners.

Choose this one if you know you want a properly firm surface. Firm pocket spring mattresses tend to suit back and front sleepers, and heavier sleepers who find softer beds let them sink too far. The pocket spring construction means each spring responds separately, so you get support where your body presses down without the whole surface tilting, which is useful if you share a bed. Published details on this model are a little thin: spring count, depth and materials aren't stated on the listing we sourced, so if those specifics matter to you, it's sensible to ask the retailer directly before ordering.

Back sleepers
The firm pocket spring surface gives a level, supportive feel under the body, which is what most back sleepers look for.

Front sleepers
A properly firm surface keeps the hips from sinking too far, which suits front sleepers who want to stay flat.

Heavier sleepers
Firm tension resists sinking, so heavier sleepers who find softer beds let them drop too far should feel held up.

Couples
Each pocket spring responds separately, so support stays where you press down and the surface doesn't tilt when you share the bed.

A firm mattress is rarely the right call for lightweight side sleepers, who often can't sink in far enough to keep their spine level and end up with pressure on the shoulder and hip. If you like a cushioned, cradling feel, or you're on a tight budget, look elsewhere.

How firm is the harrison spinks oasis 5500?

It's listed as firm. That means a supportive, level surface with limited sink, which generally suits back and front sleepers and those with a heavier build. Lighter side sleepers may find it a little too unyielding.

What sizes does the oasis 5500 firm come in?

It's available in UK Single, UK Double, UK King, UK Super King and EU Single.

Does the harrison spinks oasis 5500 have a trial period?

Mattressman lists a 60-night trial and free next day delivery with this mattress. Those are the retailer's own terms rather than a Harrison Spinks offer, so check the conditions before you buy, and be aware other retailers may offer different terms.

How much does the oasis 5500 firm cost?

It depends on the size you choose, and the price table on this page shows the current price for each size. It sits in mid-to-premium territory, which is fairly typical for a pocket spring mattress from a heritage spring maker.