The short answer to this question is, no, a deed poll is not a proof of identity.
A deed poll is simply proof that you have changed your name.
A further definition of a deed poll – The formal term for a deed poll is actually “deed of change of name” and it’s a legal document used to change the name of a person.
The only proof of identity that you’ll be able to use will be mainly your passport and sometimes your UK driving license or birth certificate.
If you have changed your name, a deed poll will be used cooperatively as evidence of your identity with other official documents, such as your birth certificate, driving license or your passport.