If I were to write the letter, I’d do a cover letter that outlines the basics of what’s been found, then either include the material, or links to the material. I have heard that emails are not always read, and wonder if this should be sent via registered mail or even messenger. I hesitate to suggest the wording, because I always end up in “what’s the matter that you can’t research this even slightly” mode—calmer heads must prevail!
Thank you very much for the input, we greatly appreciate it.