Far too late to appeal now. No big deal. We only needed to see the original Notice to Keeper. Any reminders and upcoming debt crawler letters are irrelevant.
For now, all you can do is ignore all the debt collector letters. It is perfectly safe to do so. They are powerless to do anything except to try and scare the low-hanging fruit on the gullible tree into paying out of fear and ignorance. Be being here receiving advice, you are neither.
Eventually, you will receive a Letter of Claim (LoC) from DCB Legal. When you do, come back and show us so that we can confirm it is a genuine LoC and we will provide the necessary response.
They will issue a county court claim in due course. We will need to see the N1SDT Claim Form. Only redact your personal details, the claim number, your VRM and the MCOL password. Leave everything else visible, especially all dates and times and, of course the Particulars of Claim (PoC).
It is easily defended and I can say with over 99% certainty that it will eventually be discontinued. They never go beyond the requirement to pay the trial fee. Their modus operandi is to try and scare the defendant into paying up out of fear and ignorance about litigation. Once they realise that you are not going to give up, the abandon and move on to lower-hanging fruit to pick.