to the best of my knowledge, you can legally be known as any name you wish, and you don't need a deed poll to do this, as long as there is no intention to deceive. The problem you would face is getting banks etc to accept your new name.
Hey mate, you need a deed poll to change your name with the banks etc. they wont accept it otherwise, then their is the pain with changing it on your driving licenses etc.
I think there are two different options, one is enroll the name change and register it with the government and the other one is not to enroll it.
When you do not enroll it there will be no record of your name change anywhere, only people who have the change are the HMRC, but you can even change it on the national insurance and there be no record of it. (sometimes the HMRC dont even keep a record of it)
When you apply for credit in the future all you need to tell them is previous names you have had within the last 6 years.
I done a bit of research, loads of criminals disappear this way, stupid system really. But its good for honest people who just want a fresh start drama free life.