Apologies for reopening this thread.

One additional condition that I did not consider in my original post (and would not have known about until I kindly received the working solution:
- How do I amend the formula =TEXT(COUNTIFS(B$3:B3,B3,C$3:C3,C3)-1,"00000") to show the cell as 'blank' if column B and/or C hasn't been set to one of the controlled values?
Attachment 801147
(Apologies, I can't seem to add additional attachments)