As Dave says the build sheets will have the initials of who did the build up and then at the end of that subsection (eg chassis) a checker
These sheets are held by MMC and are not shared with the customer, I was not allowed to take a photo of mine each week we went to see the progress, but it was laying around in the car to have a quick sneaky peek at
Under QA faults like this should be properly investigated and additional checks added to the build instructions
