With locations in cells A5:A35, and Departments in cells B5:B35, and
assuming an employee count by location/department in cells c5:c35...

And assuming you have a summary section that looks like this in F5:G15
Birmingham Finance
Birmingham Production
Birmingham Sales

Head Office Finance
Head Office Production
Head Office Sales

London Finance
London Production
London Sales

....you can use this formula to summarize:
=SUMPRODUCT(--(F5=$A$5:$A$35),--(G5=$B$5:$B$35),$C$5:$C$35)