Difference bewteen Due & despatch date & Sue and today date

Hi All
I am struggling with a problem. I am trying to get a formula to find the difference between the dispatch date and the due date on a spreadhseet - Now normally I dont have an issue however, IF the Dispatch date is blank, I want to have the formulae calcuate the difference between the due date and todays date. Now i ssem to have a formlua for thos ebits, but if the number is negative i only get #NUM. I also get this if the due date is in the future.

Could someone tell me where I am going wrong? Thanks a million
Due Date Differences.xlsx

Thanks MarvinP - however that has just chucked all my dates completely off kilter. they are now saying due in 2017!!

Hi Marvin,
Thats lovely thank you
How would I tweak it so that if Due date is later than today, it returns "0", and if due date is blank it returns "0".
I dont want to nest too many functions and dont know how to do it cleanly.
Thanks

Hi
Im afraid that doesnt work as cells where there should be a negative value, come back with "0".