Can you upload a sample of the workbook or place a uploaded copy to something like dropbox and add a link into your thread. Someone can take a look and hopefully provide a solution.

I've attached the spread sheet I'm working on

Hi Trevor,
it is always best that attachments should be posted on the forum, not a link to Dropbox or similar.
External links are notoriously unsafe and cannot always be used by all members depriving the OP from valuable help ( some members log on from their workplace)
When posted on the forum, the file will also be available later for other seekers to find, whereas external files could be deleted

__________________
Using O365 v2503 - Did you know you can thank someone who helped you? Click on the tiny scale in the right upper hand corner of your helper's post