Thanks for the swift reply. That answers my question perfectly. As it happens, the mistake is mine - I must have accidentally referred to your title image on the website (where the axes are marked differently) rather than the one on the board (it has been tucked inside a little plastic tube so haven't been looking at it!). May i suggest (for any other novices like me!) adjusting the title image so the axes are correct in relation to the face image? Art vs science!
I wasn't using that python script, but a modified version of one of your others that outputs a log file of all the readings and the kalman calculations. I will be adding the G calculations you described as well.
If a force greater than the maximum G setting on the accelerometer is reached, does it just show 16, or will it give a different signal?
Thanks for your excellent support, much appreciated.