No chance, this has now gone to court.
You need to file a defence or Acknowledgment of Service by 29 May, if the latter this extends your defence deadline to 12 June.
You have a defence, but it would do no harm to obtain the original PCN if you still don’t have it, using a Subject Access Request to Smart, for example. As you have noted, Smart’s PCNs used to fail to comply with the requirements of PoFA 2012, usually by being sent too late to transfer liability.
DCB Legal will probably discontinue the claim eventually, but until they do it’s a live claim and you’ll get a default judgement against you if you do nothing.
Note that Smart has now engaged DCB Legal whereas originally they used BW Legal. I have no idea why they changed, but if you search the forum you will see many cases where DCB Legal discontinues in the face of a defended claim.
My guess is that Smart is simply making a second attempt to get your money, trawling through its list of unpaid claims, in the knowledge that many court claims are ignored.
