Want to change chart data range from Kg to stones

Thanks ratcat
I've tried doing that already and I know that works with kg, but I'm not able to get the vertical axis to use stones other than selecting the data as column C as I mentioned before.
Then the chart jumps from one stone to the next as column C only uses stones and not pounds.
I would like the chart to show the same detailed changes inbetween each stone but to have half stones as the division down the side.
Column G has the detail I need (stones, pounds and points of a pound) but if I select column G as the data for the chart it just shows a flat line along the bottom of the chart because column g uses a formula and is not just numbers.