What we are doing is putting the charts in a separate workbook to the
data that they are drawn from.

This works fine in Excel 2003. But in Excel 2007 and Excel 2010 it is
really weird.

Can someone please confirm this.

1. Open a new workbook.
2. On Sheet1:make a range of data
3. On Sheet2:create a chart with "lines and dots" chart type that
displays the data from "Sheet 1"
4. Save the workbook.
5. Copy the Sheet2 to a new workbook.

Notice that in the new workbook there are lines connecting the dots on
the chart.

Now close the first workbook with the data. Notice that on the second
workbook the lines have gone but the dots still show up where they
should.

Now open the first workbook with the data. Notice that on the second
workbook the lines are back.

Now close the first workbook with the data. Notice that on the second
workbook the lines have gone but the dots still show up where they
should.

If the dots don't disappear then why do the lines?