Man, what hard work!
I'm trying to convince a spare parts guy at a very well know German maker of top quality sporting goods that the fixing I require to renovate one of their products exists.
I was hoping that the photograph of the part (a brass threaded bushing and matching bolt) with a description of where it was from would be enough.
"Not ours!" he says. "Well, it looks original to me" I reply.
Hopefully the photograph of the area it is mounted to with an added diagram (yes, I busted out Adobe Illustrator) helps him recognise it. If not, I'm stuffed (and/or writing to the head of the company to moan about it!)
The Australian company I deal with for similar equipment has an old guy who'll ask you a question like "what shape is the bit that goes from X to Y?" and then proceed to tell you what year range it was built in and then get you the right spare part for that design generation. I'd have thought that Mr German would have been much better at this!