Thank you Belanger. I wanted to make sure it wasn't some specific symbol, we will just let our customer know that we are not responsible for any meaning or requirements due to this if they are unwilling or unable to supply us with this information.
I've googled and looked at charts, tried reverse image but am unable to find the meaning of the hexagon shape (split into 3 sections) or the numbers / letters inside them. They seem to usually be near a Feature Control Frame (not sure if they are some type of key characteristic signifier or ...
