I have to convert a coordinate from UTM to MGRS. I think I have the most of it covered, but I have some difficulties to calculate the correct Latitude-band. How can I decide which band the coordinate has?
Bear with me on that, and I'll check my library
Then zone will be 25, which I think is correct. Try it and let me know if it works for you.
There is also:
I am sure you can get into the JS and use the code.