Hi Leslie,
I'm using Nitro Pro 11.0.3.173 which I'm sure is the most up to date version.
I've just gone into preferences, where "the irritated computer user thing"......... I stumbled on Units and Grid, which I've never made adjustments. The height between lines and width were set to 25.4, with my Unit of measure as mm.
I changed this to 1, and 1mm for precision, so its seems to be fine now.
Thanks for your attempt to help me, where this may be a simple solution for anyone else who encounters this problem.
Thanks Stan