Nearly one in five Britons are tossing and turning at night, with bedroom temperatures often to blame for disrupted sleep. To combat this, experts suggest a myriad of solutions, from steering clear of caffeine before bedtime to the quirky tip of refrigerating socks for those overheated evenings.

But there’s another trick gaining traction, one that’s commonplace overseas yet relatively unheard of on British shores: separate duvets for you and your partner. Sleep specialist James Wilson, also…