It would be advisable to submit evidence of your requests (copies) and evidence that they have been received to the court prior to the hearing with your witness statement. Note in the covering letter that you will be bringing the originals to the hearing (with your own copy of the witness statement for reference) and that they will be available upon request of the judge.
Your points in the "response for the SD" seem reasonable and my only advice would be to make your witness statement concise and to the point.
Make a point...refer to the evidence.
The judge may see many letters and lengthy documentation from individuals. He may make more sense and a more reasonable decision of a concise document with evidence to refer to as he wishes.
Last point should be your conclusion...
example "I respectfully ask the court, that in light of the aforementioned witness statement and supporting documentation, the credit agreement is deemed unenforceable and the statutory demand be set aside"
please note - i am not a legal representative