My husband has had this problem since September last year. I usually put either a fabric or disposable inconti-sheet/bed pad under the bed sheet as he'd either take it off (don't need it, don't have a problem) or fidget so much, it comes off. I know the sheet still needs tobe washed, but it saves the mattress smelling. If we're allowed to mention brands, Huggies bed pads are best as they have sticky strips (found in baby products aisle). For men, Boots have adult pull-ups designed for men, so far, so good. Otherwise Sainsbury's own brand is cheaper (£5.99 for 10). otherwise try a mattress protector from a mobility showroom as she should be entitled to vat exemption. I hope this helps. Oh yes, if my hubby is anything to go by, she MAY go through a phase of 'I'm not wearing them, I don't wet the bed'. Getting strict and honest with her may help.