well could be Z or N dont know. But still the marks and stile of item are thypical Hanau. Also remember there are 1000th of Hanau marks that are not listed at this page.
The Z is pseudo-Zurich, but Zurich never used a round punch to my knowledge. I don't claim to have any experience in tracking Hanau makers from their pseudomarks, and so don't know who it is, but it might be a starting point for your research if you are keen to find a maker.