For a little follow up comment, in the US, the Brusso brand might be looked over to confirm to one's satisfaction, but has a long, consistent high quality reputation. They may(?) be where the folks at PDyson source their hinges. Along with butt hinges mentioned by Damascus, there are also things called stop hinges, that hold a case cover open at just a little past 90*. By coincidence, 1 1/4" and 2" hinges have an uncanny similarity to 32mm and 50mm European spec hinges.
I don't know if they would fit this project or not, but I also noticed that the US version of the bay has them for seemingly good prices, and the Lee Valley place I mentioned has all brass piano hinges for that option. I have used the Brusso brand for a fair number of similar projects, but admittedly not for a one for one replacement repair of a wood gun case. I'm sure there are many options, best of luck with it.
