Re: From a user's point of view...
If I remember this correctly, in UK common law your official name is simply that by which you are usually known, which does not have to be the one on your birth certificate. Regular use could be sufficient. An advert in the local paper puts an official seal on it and deed poll is not essential. However this tends not to hold much sway with the various organisations who demand proof of identity. I did a quick Google search which confirms some of this