Formatting the y-axis of a chart

Originally Posted by teylyn

Ah, the light just went on.

See attached for the method mentioned by Andy applied to your chart

A dummy series with X values of the lowest value on the X axis, combined with Y values of even distribution. The data markers sit on the Y axis. Use the XY Chart Labeler tool http://www.appspro.com/Utilities/ChartLabeler.htm for easy creation of labels for the data points to the left of the markers, then remove the axis labels.

I've left the data markers for the dummy series visible, but you can set them to no markers to hide them.

Just make sure that your primary and secondary Y axes have the same Min and Max settings.

Thank you for your effort. It certainly has achieved what I specified, that the printed numbers do NOT 'start' from the minimum value in the data, but at the 'rounded' figure of 400. However the horizontal 'axis' is at or just below a minimum data point/value, instead of at 400 - similarly the other horizontal line is not at 500 but at 480. Cosmetic maybe, but different from my expectation.
If falls short of my expectation to the extent that the horizontal lines are