The Silentnight Air Plus 1200 Mirapocket Mattress is a plain, medium pocket-sprung bed with no foam in it, and that makes it a fair buy for side and back sleepers of average build who run warm. Avoid it if you're over about eighteen stone or sleep on your front, because you need a flatter, firmer surface than a medium grade gives you; go one rung up the range. Silentnight has never excited me as a brand, but the build under this name is sensible.
Full-height pocket springs, firmer through the middle
The support is 1200 Mirapocket springs, Silentnight's pocket springs, each in its own fabric pocket so it moves on its own. The listing doesn't say which size that count is for. It's a modest count, but every one is a full-height spring with no mini springs padding out the total, and I'd take that over a bigger number made of minis. The unit is zoned in its centre third, firmer under your back and hips. Zoning works when it lines up with your body, so a very tall or very short sleeper may find the firm band in slightly the wrong place.
A rod edge border runs around the perimeter of the spring unit to stiffen the sides, so the edge dips less when you sit on it. Take that seriously on a double, where the two of you need the full width.
Fibre on top, which keeps it cooler
Above the springs sit Silentnight's Air Plus fibres, sold on letting air move through the mattress, then a layer of soft white fibres and a knitted cover. Fibre over springs sleeps cooler than a memory foam top. I keep a heavy duvet on all year because the weight settles me, so the cooler build underneath is the one I'd choose. Fibre does settle a little in the first months. Rotate it head to foot from the first month, since it's one-sided and rotating is all you can do; I'd always prefer a mattress I could turn. Check the guarantee too: download Silentnight's from the listing and read what depth of dip it pays out on, because most guarantees ignore softening.
At 26cm (about 10in), most fitted sheets go on without a fight, and it comes in every size up to a superking.
Where it sits in the Air Plus range
The Air Plus range runs from the 800, graded Medium to Firm, through the 1000 at Firm, to the 1400 Ortho at Extra Firm, and this 1200 is the medium one. More springs here don't mean a firmer bed, because Silentnight sets the grade separately, so choose by feel first and count second. Side sleepers and lighter back sleepers belong on this one. Heavier back and front sleepers should step up to the Air Plus 1000, and can ignore the "Ortho" on the 1400, which only means firmer.
The few reviews on the listing were written about the Silentnight British Wool 1800, the deeper wool mattress it sold before, so judge this one on its build.
What to buy instead
If you want firmer, buy the Air Plus 1000. If the budget stretches, a turnable pocket-sprung mattress from Hypnos or Relyon is better made to my mind, and turning it shares the wear across both sides.
