You ignore EVERYTHING from DCBL and any other debt recovery company. They are powerless to do anything except to try and scare the low-hanging fruit on the gullible tree into pay up out of ignorance and fear.
You can safely ignore that and any similar letters. However, what is not clear is why you appear to be confused as to how a debt recovery company can trace you. They do a simple credit reference search that costs them less than 50p in bulk.
Now, think back to 2nd August 2023... why address would have been on your V5C registration document at the time? If you'd moved previously and not updated that document, then the only address MET Parking Services would have for you would be the address on the V5C. So, if you no longer lived at that address and did not have any post forwarding service in place, you would never have known about the Parking Charge Notice (PCN) that had been issued to you, the Keeper of the vehicle.
Fast forward to now... have you ever updated the address on your V5C? Updating your drivers licence does not automatically update your V5C registration details. Your drivers licence is specific to you as an individual. Your V5C is specific to a vehicle.
Now MET has two possible addresses for you. What's the odds that if they decide to issue a claim for the alleged debt that they will issue it to the old address and you end up with a CCJ by default because you never responded to it because it went to an old address?
The very first thing you must do is sent a Data Rectification Notice (DRN) to the DPO at Met Parking Services Ltd, instructing them to update your current address for service and to erase your old address. The highlight words are there for a reason... use them.
The second thing you can do is send a formal complaint to MET explaining that the very first you have heard of this alleged debt is a letter from DCBL, who you will not be communicating with as they are nothing more than a third party, unconnected to any contract allegedly breached by the driver. It is possible that an outdated address was on the V5C at the time and you have now sent a separate DRN to their DPO to correct this issue but you now require sight of the original PCN in order to have any understanding of the issue.
If you do nothing, you risk getting a CCJ by default. If you only do the DRN, then it is highly likely that you will, in due course, receive a Letter of Claim (LoC) from the incompetent sister company of DCBL, DCB Legal. This will eventually lead to an N1SDT Claim Form from the CNBC being issued, which you definitely cannot ignore.
Suffice it to say, as long as any claim issued by DCB Legal is defended, no matter how weakly, it will eventually be discontinued. However, if you are unfamiliar with the process, you are likely going to go into full panic mode and screw something up. If you follow the advice you receive here, you won't and you'll never have to pay a penny to MET.
