You have to estimate and match the 3 pieces to fit together
Bah! Thought this might be the case.....
My work around is to use a grid test pattern and "physically" measure on the screen where the centre of my overall grid pattern should finally end up..... Then align the left and middle to this, before finally aligning middle and right.
Not the most scientific approach, I grant you, but as a workaround it seems to work ok(ish!)
Will keep the forum posted if anything changes.....
Also, Roger, are there any updates etc etc planned in the future??? Not sure what could be, but I'm sure there's ideas !