There are houseplants called "citrosa" which have a lovely lemon-y smell that mosquitoes just hate and avoid coming near. You could keep a few of them inside your house, next to your bed and by the windows. They are not beautiful (they look like geraniums without the flowers), but I love their aroma, and they seem to work. They are easy enough to take care of. I bought mine from a supermarket that had a garden section. This was in America, but they must have those plants for sale in Britain too. Try inquiring at a garden store. Good luck!