A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
OK, got it sussed. MS say:-
| It is best not to include row or column headings in the selection. If you select the headings with your data, the chart may produce incorrect results |
|---|
I therefore excluded A 1 to C 1 from the underlying data and the bubbles duly moved over to the right hand side.
This item is therefore closed.
Apologies for posting.