Googling "Navtec hydraulic fluid reservoir" shows photos of identical unit and some other system parts
& info if anyone's interested.
I copied the photos originally posted and asked Google
to search for similar photos & got nothing. It's often worked before but it seems like Google's been dumbed down over the last year or two.
It's easy to tell that some of the recent suggestions (after #23) are just for fun but others seem to be still guessing away at it