I recently switched to Octopus for our electricity bills and so far have been really impressed. I think they were also rated really highly for customer service in recent polls.
If you want to use my referral link, then it will give you a free £50 credit to your bill when you switch to them, along with the same for me.
Thank you so much if you use my link! 
share.octopus.energy/good-shrew-537