so I have found a pretty fundamental flaw with the gridline offset function when displaying gridlines in Elevations please refer to my attached screenshots below
East Elevation - I have shown the gridline B with a 700 offset (to the right towards Section Section Marker D) to avoid conflict with the Section E marker.
When I go to my West Elevation (which bear in mind is a mirror image) the gridline B marker is also shown offset to the right but this is incorrect the marker should be offset to the left (away from marker D towards marker E as it was in my East Elev) instead the gridline overlaps marker E completely (as shown in screenshot with ghost turned on) towards Section Marker C (completely the wrong direction) if i proceed to correct this it will then make it display incorrectly back on the East Elevation (rinse and repeat) so I will have to patch and fill this with 2d elements or instead offset the section marker heads (hopefully i wont end up with the same issue as above)
edit: in the end I have extended the section marker so it is the only marker that doesnt line up with the others and kept gridline B without an offset, (not ideal) but the marker offset is not working correctly.
There is interesting solution that many ArchiCAD users might not know.
If you select "Custom" from drop down menu instead of "General" in Section/Elevation tab in Gridline settings, then staggering and gridline height will apply only to this Elevation.