We have a lovely futon from the Futon Company, which I find very comfortable, but one or two of our guests have gently mentioned it's a bit firm for their tastes
As we'll be allowed overnight guests again soon (woohoo!) I've been thinking about getting a mattress topper for their comfort. Can anyone recommend one? I know the Futon Company themselves do one, but I can't find any reviews, which makes me nervous. So I'm turning to the Mumsnet hive mind 
If you've landed here looking for suggestions, we've recently updated our best cooling mattress topper page with the products MNers love - including options for all budgets. We hope it's useful!
MNHQ 