Perhaps this is the reason.
Quoting from "Creating and editing charts" in the filemaker help system:
"FileMaker Pro does not recognize individual values in repeating fields as a data series. To chart data in repeating fields, use the List function to combine repeating data in a delimited format, then choose Current Record (delimited data) for Use Data From."
Ahhhhh.... now I see. Takes a bit of fiddling around but I got it. Thanks!! :smileyvery-happy: