Charts dont refresh to show changes to data sheet

Hi All

I have a reporting system in Excel with all my charts on one sheet and
then one sheet per chart with the data on.

When the user changes different configuration and data sources my VBA
whirs away and modifies all the data sheets as appropriate.

What has happened is that all of a sudden changes made on the data
sheet are not automatically reflected on my charts. For example, even
something simple like changing the name of a series on a data sheet is
not reflected in my chart! I try a F9 to force calculation and still
nothing. I try to reset the source data and it still does not update -
this is really weird!

I found by chance that if I change anything on the Y axis (say Scale
or Number) click OK and then click Undo then the chart will update
correctly! Madness! I have to do this to each chart to force it to
update correctly.

What can I do to force all the charts to match exactly the data
sheets? I have tried getting the workbook to recalulate and increased
my calculation iterations as well but with no success.

Can someone please give me a check list of things I can try? This
problem is casuing my excellent system to look like trash! ;(

Thanks in advance for any ideas,
Chrisso