Dorma Full Forever Anti-Allergy Mattress Topper reviewed

The Dorma Full Forever Anti-Allergy Mattress Topper is the standard Full Forever with its recycled polyester spiral fibre coated in Aegis Microbe Shield, a treatment Dunelm says prevents the growth of bacteria. It keeps the 230 thread count cotton cover and the 3cm or 6cm choice, and costs £10 more than the untreated Full Forever in every size, starting at £70 for a 3cm single at the time of writing (September 2026).

What the anti-allergy treatment is

The treatment is a biocide, and the Dunelm product page names it in full as dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride. That disclosure is a legal duty rather than a courtesy. The Health and Safety Executive’s guidance on treated articles says that when a treated article is sold with a biocidal claim, its label must state that it incorporates a biocidal product and name every active substance in it. The claim Dunelm makes is anti-bacterial. It does not describe the topper as a barrier against house dust mites.

What helps with a dust mite allergy

For dust mite allergy, NHS advice points to covers and hot washing rather than treated fibre. Patient advice from Cambridge University Hospitals NHS Foundation Trust says of barrier mattress covers: “This is the single most effective measure but is not enough to help on its own.” Allergy UK adds that washing at 60°C or above kills mites. On an allergy-prone bed, this topper therefore works best under a fully enclosing, washable barrier cover.

Washing the topper itself is unclear. The care bullet on the Dunelm page says spot clean only, while the product description calls it machine washable. We follow the care bullet; check the sewn-in label before putting it in a machine.

Prices against the standard Full Forever

Regular Dunelm prices, checked on 28 September 2026; dimensions as Dunelm lists them for this model.

Feel, fit and returns

The feel matches the standard model, springy rather than sink-in, which we rate medium-soft at 3 out of 10. A 3cm walled edge and elasticated straps keep it square on the mattress. Dunelm states no guarantee, and there is no sleep trial. Under Dunelm’s returns policy, toppers are only refunded on a change of mind if returned unused and sealed, an exception the Consumer Contracts Regulations 2013 allow for hygiene-sensitive sealed goods. Dunelm shoppers rate it 4.6 out of 5 across 213 reviews (September 2026).