A mattress you cannot afford to replace is usually a comfort problem rather than a structural one. A topper fixes the comfort layer without replacing the bed underneath it.
Natural latex over memory foam gives you both behaviours at once: the latex pushes back and keeps you level, the memory foam gives at the hip and shoulder. Take the 6cm for a small correction, or the 9cm if the mattress underneath is genuinely too firm.
Natural latex over a memory foam base
Two depths: 6cm and 9cm
Four bed sizes, 120x190cm through 150x200cm
Latex keeps the spine level; memory foam relieves hip and shoulder pressure
