*IMPORTANT* CGPA Application Question

I graduated from a university in London, and my transcript lists my result as First-Class Honours. I had my transcript converted and approved by my university, but when completing the online application, I’m unsure what to enter in the “Original CGPA” field.

The instructions say to enter the CGPA exactly as it appears on the original transcript and then list the converted GPA below. However, my transcript doesn’t include a GPA or percentage—only the classification—and the system won’t accept “First-Class Honours” as an entry.

This is the only part of the application I haven't completed and would prefer to get it sent out today/tomorrow morning. Does anyone know what I should put in the Original CGPA section so I can complete my application?