You have not received a summons. This is not a criminal matter. You have received a county court claim for an alleged debt, from ECP, issued by DCB Legal.
What is the “issue date” of the claim?
This is very easily defended and I can say with better than 99% certainty that they will eventually discontinue.
You say that you updated your address with the DVLA. Did you update both your drivers licence and the V5C? Updating one does not update the other. Is the N1SDT claim form addressed to you at your current address or has it been handed to you from somewhere else?
If it is addressed to you at your current address, then that is ok. If it isn’t and you did not receive any Pre Action Protocol correspondence such as a formal Letter of Claim (LoC), you will have even more for your eventual defence.