Hi Gents,
The Gazelle uses the following system
grid number from 1 to 60 with some special cases with grids 31,32,33,35 and 37 (https://en.wikipedia.org/wiki/Easting_and_northing grids map)
the display shows
northing 1st line (x10 meters)
easting 2nd line(x10 meters)
Grid number 3rd line
This third number can be displayed/edited pressing the down arrow.
Hope this helps.