I picked this watch up over 9 years ago. Usual car boot find in the UK on one of my typical Sunday hunts back then. It was unmodified and still 100% as original as I could tell. Usually when I get a vintage watch with a metal band it is a Spidel and I am apt to change them out in a heart beat. In this case it was not a Spidel and looked to be right for the age of the watch so I left it on. Took it to my watchmaker at the time and had it serviced.
I always found the jewel configuration odd on it until I managed to pick up a Zenith 135 at the same sale. From what I can see is that it has an off set center wheel. For the 135 that was to help make room for a larger balance wheel for the time trials that they took part in. Obviously this trend went on to other makers for their movements as well. I have no idea if Vertex ever took part in trials or anything. I just found the layout interesting and the movement is rather flat as well. The overall watch is very slim. Down to details now lol.... The movement is marked as you can see for a 17 jewel Vertex Revue 350 cal. There is a GT mark under the balance. Apparently the movements were made by MSR (Manufactures d'horlogerie Suisses Réunies).
I found that a lot of the MSR movements share the same train configuration. Anyone else have any experience of knowledge about these movements?