Ensure 24 hour cover for staff rota

Hi all,

I'm creating a rota where at least 2 staff members need to be working every hour, every day, 24 hours a day.

Each week will have different shifts and changes will be made continuously so I need an easy way to identify gaps in the rota.

Currently, I'm using conditional formatting to alert me if less than 48 hours have been scheduled per day, but this is a temporary solution as it doesn't help if more than 2 shifts overlap at once.

I'm using Excel 2003.

I've attached my current work. Any help will be much appreciated!

Never mind, I've found the answer here.

I'll look longer before I post next time!