You can safely ignore Empira. They are nothing but a powerless debt collector and cannot do anything except to try and scare the low-hanging fruit on the gullible tree into paying out of ignorance and fear.
What you cannot ignore is the fact that you most likely did not update the address on the vehicle V5C after your last change of address. Updating your drivers licence does not update any other DVLA data and you can check online if your V5C address is correct and change it if necessary. However, the issue is that EPS now hold two possible addresses for you and they cannot have a second bite at the cherry to obtain your current address.
If the V5C address is incorrect, then you need to send a Data Rectification Notice (DRN) to the DPO of EPS and instruct them to update their records with your current address for service and to erase the old address. The highlighted words are there for a reason and must be used.
If you don't so this, EPS can simply issue a court claim to the old address and you would know nothing about it until a default CCJ appears on your credit file. So, get that done as a priority.
As you have never received the original Notice to Keeper (NtK), you can send a formal complaint to EPS and request a copy of the original NtK and require them to evidence the actual date they sent the NtK.
Apart from that, there is little else you can do at this stage. Ignore all debt recovery letters. If/when you receive a Letter of Claim (LoC) come back and we can advise on how to proceed.