I would like to know if the following is possible without changing the way
that my data is structured.

I have three data tables - one showing total scores by three age groups,
another showing girls scores (again by three age groups) and the same of boys
scores - although there is more than one row in each of the tables.

I want to select one row from each of the tables to construct a graph.

This works fine and I am able to construct the graph. I then however want
to flip how the bars are displayed (so that the items that are listed in the
key are now on the x axis and visa-versa).

Normally I go into source data and click on the data range tab and then
select the other checkbox (that the one already selected) in the series in
section.

However, this is greyed out (presumably because the chart is complex). Is
there any way to do this - without constructing more tables (as I have a lot
of similar things to do).

Thanks for your help.