It's too late to appeal. You can safely ignore the debt collection letters, even if Moorside Legal is issuing them.
What you are waiting for is a Letter of Claim (LoC) that will come from Moorside Legal. This will eventually be followed by an N1SDT Claim Form from the CNBC. This is what you want.
Moorside Legal will screw up the Particulars of Claim (PoC) and you will have a very valid defence to get the claim struck out for failing to comply with CPR 16.4(1)(a).
So, ignore anything except an LoC or, more importantly, an N1SDT Claim Form from the CNCB. Show us when you receive them and we will advise further then.