A while ago I read a list of 'small purchases that have changed your life'. On it was an electric toothbrush, with the argument that:
After having used one for a year, I can report that it doesn't do anything for me. It's fine; it's not like I'm going to throw it away, and I'll keep using it now that I have it, but I don't perceive any benefit from it beyond a cheap manual toothbrush. My teeth don't feel remarkably cleaner than before, and it's just a little bit more hassle to clean and maintain than a manual one.
It's possible that I am just better at brushing manually than the original recommendation author, or conversely I could be much worse at brushing electrically, or maybe I bought a bad model, or maybe my teeth are just different from theirs. But with no experience other than my own to go on, this is a non-recommendation from me for electric toothbrushes. Save your £50 and keep using your manual one.