The Gov website has the wording to change your name by deed poll which just needs to be signed and witness by two witnesses.
I was going to do this as it's free. Then change my name on HMRC website and then bills, bank, driving licence and passport.
But I have heard some places wrongly challenge the use of a free deed poll and prehaps I am better off paying for one of the online services (surely it's just a certificate on their paperwork - same wording still needs signing and witnessing.)