Hello! I completely understand your reasons for wanting to change your name, and I'm in precisely the same situation myself - though I picked my name several years ago, now, and use it wherever I can! In my case, I intend to change my name in its entirety: for my forenames I chose names important to me on a personal level, for my middle names I chose figures I admire, and for my surname, I chose the figure I admire most of all
I just wanted to ask - as I have done a bit of Googling on the matter for my own situation! - are you set on changing your name by Deed Poll? Would you consider a Statutory Declaration, instead? I ask because, as far as my own research indicated, it seems the latter carries a bit more weight with banks, for example, and other places that might ask you for more stringent proof of your name-change, unless of course you opt for an Enrolled Deed Poll, but that is a bit more complicated, and you need the aid of someone who has known you for more than 10 years, but isn't a blood relation.
A Statutory Declaration needs to be witnessed by a solicitor (or another important figure, like a notary public), which I imagine would cost a slight fee, but shouldn't take more than 20 minutes of their time, if you drew up the declaration yourself! (And there are plenty of examples of name-change declarations online.)