If you are wanting to change the customisation of the report, you will need to click into the report, select Customise and once changed select Save customisation. Save this as the same name of the original customisation - this will then overwrite the previous settings.
Many thanks. Now I'm in the right area. However, I now find that I cannot select invoice dates rather than due dates. I'm just trying to list all invoices dated 1st-31st July. Each time I try to choose a date it ticks the Due Date box. Please advise.