Basa,
Study the witness statement.
If someone claims to recollect something from 8 years ago then you need to know why they would recall yours. What other information did they process that day - doubt they can remember. Its too late to call the author as a witness but these "Witness Statements" will often be written by the legal department to be bullet proof but not be a true account.
Also the McGuffick case refers to an acknowledged "compliant agreement".
"3 On 3 October 2005, the claimant entered into a fixed-sum regulated loan agreement with the bank under which the claimant received credit in the sum of £17,034. The total amount to be repaid was £20,781 in 60 monthly instalments of £346.35. It is not suggested by the claimant that the agreement was in any way improperly executed, so that sections 61, 65 and 127 of the Consumer Credit Act 1974 are not directly in issue."
So the relevance is questionable. The challenge was the legality of the the CRA reporting;
"The relief sought
3 (3) A mandatory injunction requiring the bank to notify CRAs to whom it has previously reported the state of the claimant's account either (i) that from 11 March 2009 onwards (the date when the 12 working days prescribed period under section 77 expired) the claimant has not been in default under the agreement or (ii) that from 11 March 2009 onwards, the claimant has defaulted on the agreement in circumstances where through the bank's breach of section 77, he has no enforceable liability to pay."
In effect, since s78 had not been complied with, the creditor entered legal default which it acknowledged it could not clear, since the executed agreement could not be located. Thus, the legal right to refer the payment history to a CRA, should be constrained by the enforcement restriction brought about by non-compliance to s78. Since CRA reporting is not a term of the agreement, per se, RBS were able to argue that CRA reporting did not breach the constraints placed upon it by a defaulted agreement on the part of the creditor.
How they propose to link this to your case is a contained in para 106 to the end of the document.
S