Open 24 hours without the 24 hour menu

Why is MCDonalds in Ottery the only branch that does not sell everything on the menu this time of the morning? Management and stuff are just lazy and unprepared because if you can buy a BigMac at 4am why can’t you buy it at 6am....then why advertise that you 24 hours. They also never seem to have milkshake or ice cream. It’s pathetic seriously!