Planet X are selling their own brand overshoes for £8!
I don't usually advertise firms and have no financial interest but I have found these to be good in the past,
Easy to put on, warm and protective and a bargain price.
Have a look at their other bargains as well e.g. bib tights ready for the winter.
https://www.planetx.co.uk/i/q/CLPXOSH/planet-x-neoprene-overshoes