I have recently switched energy providers, gas and electricity, to Bulb.co.uk. The signing up process was quick and simple. Communication from Bulb has been excellent. Their gas and electric tariffs are extremely reasonable.
In addition, I got a £50 referral for signing up. If you wish to sign up you can use my link below to get £50 for yourself. (copy the link, but remove the space in front of the /)
bulb.co.uk/refer /douglas6661
Good luck.