Question: what documents do you need to change your number plate?
Answer: Proof of Identity: Driving licence. Bank/Building Society statement issued within the last six months. ... 
Proof of Entitlement: A Vehicle Registration Certificate (V5C) (Please be aware only the new red V5C Certificates are accepted, and not the old blue V5 Certificates) The tear-off slip (V5C/2) from (V5C section 10)