IMO The judgment shows up may misconceptions that you see on here and elsewhere.
First is that an agreement cannot be enforced if there is no actual copy present, plainly it can. If you are going to use the fact that the creditor cannot produce the agreement then you must also make a statement that either there was never an agreement or that there was some defect in the execution in addition to the missing document.
Secondly that a minor defect on a default notice cannot be considered as de-minimis after the Brandon appeal. As illustrated here, all the Brandon case showed was that the minor defect should not be dismissed without consideration, it can still be considered as irrelevant by the judge dependent on the facts of the particular case.
Then there is the matter of the section 78 copy, in Roberts was held that all the documents must be sent together, where as here the judge was quite content that the copies were sent at different times.
I think that if you compare this case with say Harrison one of the main things that hits you is the attitude of the judge towards the debtor, in Harrison he was much more sympathetic, in this case he seemed(reading between the lines) almost annoyed that the debtor was using the technical points in order to avoid payment. A lesson to anyone considering challenging an agreement, try and get the judge on side, stress the prejudice incurred rather than depending on technical defenses. IMO