I think the names 'cam follower' and 'diverter valve' etc. are names given by independent garages/us forum folk. The official VW names for these parts is something different (unsure what exactly - maybe someone can find out?), hence the confusion.
I had a similar situation when my car was in for a service: I asked them to update the cam follower. They didn't have a clue until I provided them with the part number.
As somebody else has mentioned, just give them the part numbers to avoid any confusion.