Your drivers licence and V5C are not linked in any way. If you update your drivers licence, it does not automatically update your V5C, which must be updated separately.
So, physically go check now. Please confirm whether the address on the V5C is correct and was it correct at the time the PCN was issued (not the court claim).
If the CCJ was issued by default because you never received the claim due to it being served incorrectly to an address you did not reside at, then you can apply to have the CCJ set aside under CPR 13.2, which is a mandatory set aside.
There are other arguments which will depend on the circumstances of the original claim and even if set aside, may be allowed to be re-served. However, there is also a good argument to have the original claim struck out.
Do you have a copy of the Particulars of Claim (PoC)? If not, you need to phone the CNBC and ask them to email you the PoC while you wait on the phone. Be prepared to wait for a while. Call first thing in the morning around 0830 for the best chance of a shorter waiting time.
Also, ask them who the Claimant is and which, if any solicitor represented them.
You must act promptly when discovering a default CCJ and any delay in applying to have it set aside will be questioned by the court.
You will need to file an N244 application for the set aside. There are two options, an application with consent which will cost £119 or without consent which will cost £303. The difference is that with consent is by agreement with the claimant and does not require a hearing. However, the claimant has to agree and is unlikely to agree to paying you back the £119 application fee. Without consent means that you are applying for a hearing and are able to request your £303 application fee be paid by the claimant, especially if they can be found to have acted unreasonably by not being diligent in trying to find your actual place of residence.
You will be required to submit a Witness Statement and a draft order for the set aside and also a draft defence for the original PCN. You seem to be aware of having received the PCN back in 2018/2019.
At the time of the CCJ, were you there to be found? Were you in the electoral roll? Do you have utility bills in your name at the location you reside at? Do you have a bank account in your name with your current address? In other words, would any credit reference agency be able to find your current address for the sake of a bulk credit reference search?