That's brilliant, thanks very much! I even managed to set up my Reset macro to add the word 'Reset' and delete it from the cell that is being validated to figure out whether the checkbox should appear or not.
Could you please help me figure out how I can get this to work on leap year? The calculation is clearly out by a day.
I want this to be flexible enough to work whether the dates are in a leap year or not, but it should always be looking at whether within the full financial year (up to and including 31/03) there is an additional day.
Thanks for your reply, the output is the same when I try replacing the formula with your suggestion. What else can I try? Is there a way to make Excel look at the period 01/04/YEAR to 31/03/FOLLOWING YEAR to check for a leap year day and then start the calculations after that?
It would need to look at the dates entered and identify whether the end date input in C6 comes before 01/04 the following year and whether before 01/04 the following year, February contains an extra day.