So after finally realising my printer doesn't like Tn commands and also doesn't use M140 and a few other commands, I managed to get my printer working correctly

. However because my home location is at zero position (0.0, for x/y) the graphical yellow bed polygon shows the print bed (bottom-right corner) location in the centre of the platform.
This is incorrect clearly and only a visual thing; so my question is how do I adjust this without messing with my printer settings (because they work)?