I have created a chart from a saved view with a Filter & published to a Dashboard but there is no option on the Dashboard to adjust/modify the filter
I am aware that best practice if using a filter on a Chart is to publish with all items filtered and then work backwards from there but I cannot find where you adjust the chart filter on the Dashboard....maybe I'm blind??
No, you are not blind. You need to go back to the line item (the filter logic) where you currently have it as TRUE and update the logic.
Yup of course - I was thinking about opening the Filter button but this must not be available on Charts, only on the data that it is chartered off