There's a proper Hypnos build in the Bespoke Amethyst Mattress for less than most of Furniture Village's Bespoke range, and heavier sleepers who keep off their sides should buy it. Side sleepers should walk away. Extra firm is a narrow buy, and this is very firm indeed.
The step up from the Amber buys more springs and traceable wool
The Amethyst sits one rung above Furniture Village's Bespoke Amber, and the extra goes on three things. You get 1,200 springs in a king, ReActive 7-turn ones, against the Amber's 1,000 6-turn, Woolkeepers wool you can trace to the farm against the Amber's British wool, and 25cm of depth against 23cm. Both are extra firm, both are hand-tufted with two rows of side-stitching under a cotton cover, and both are made by Hypnos for Furniture Village alone.
The springs are what I'd pay extra for: more of them, each with an extra turn of wire, under a heavy sleeper. The traceable wool is a nicer filling with a better story, and wool breathes. The eOlus fibre in the fillings is Hypnos's foam-like comfort layer, and Hypnos says it won't hold heat or moisture. Take it as a pleasant extra rather than a reason to choose this one. Hypnos is a maker I rate, and this is its build at a fair price.
Very firm, for the bodies that need it
The handful of owners with something to say agree with the label: very supportive, very firm, and one calls it "fantastic if you want an extra firm mattress". Another mentions side handles that make it easy to rotate. Extra firm works for back and front sleeping, and for heavier bodies that sink far enough into a mattress to feel held by it.
I sleep on my side, and extra firm is the one grade I would never put under my own shoulder. Side sleepers and lighter people should avoid it and buy something softer.
Rotate it, never flip it, and check the slats first
With one sleeping side it gets rotated, never flipped, and a king weighs 36kg. Furniture Village's care notes ask for slat gaps of 7.5cm at most, warning that wider ones can make the mattress sag and void the guarantee. When it arrives, leave it four hours to air and for the springs to settle. Expect a slight body impression as the wool and fibres bed down: the care notes treat that as normal wear rather than a fault.
Furniture Village charges for delivery and doesn't list a sleep trial on it, so a wrong choice is costly to undo. Be sure extra firm is right for you before you order, and compare the price with the Amber in your size.
What to buy instead
If you don't need the extra springs or the traceable wool, the Bespoke Amber is the same idea for less, and still a proper Hypnos. Side sleepers should skip both and look at a medium-firm pocket-sprung mattress with natural fillings.