I don't blame you for not trusting them
I had to retake my test a few years back. I only sent mine off to get the address changed.
It cost me a lot of money even though I only needed a 30 minute refresher to get used to the training school 125, as I failed the test twice. First time for speeding (didn't spot a speed limit change from 40 down to 30, so fair enough) and the second time I got lost andthe examiner gave up and went back to the test centre. That took a lot of living down.
Then I had to have the Harley restricted for two years as the training school couldn't find a bike I could touch the ground on so no direct access. Try explaining that to your insurance company.
All in the past now, but not a happy time. You are right not to trust them, although I think they now accept proof of photo copies etc.