My Mum is having to sleep on her back at the mo due to a pelvic fracture (it hurts to try to turn on her side) and she says the mattress digs into her. It`s quite an old mattress and I thought I might get a topper to make it softer. I know there are memory foam ones but have heard they can be quite hot. I`ve stayed in hotels where there is some sort of topper incorporated in the mattress and they are really comfortable. I`d like to get something for her. Can anyone recommend something?