Victor Delta wrote:
I have an Excel chart where one of the sets of data (vertical bars)
would be better displayed on the underside of the x axis (i.e. negative
instead of positive). Is there any way I can make this happen using the
chart formatting features?

If not presumably I shall create another column to calculate the
negative data, and then plot that.

That is indeed your best bet.

Additionally, a stacked column chart will avoid staggering the positive
and negative values along the x-axis.