Took off the old cateye today and put the mount on for my Garmin.
Surprisingly the stem length and shape didn't allow for the mount to go on the stem, and the same problem with the height of the stem vs my bars.
I had to wrap a bit of handlebar tape around my bars to get some height, so I could mount it. I suppose I could buy the special mount for in front of the stem but I can't bring myself to forking out the money for something so simple.
Anyway, I'm happy with the result as is...