"Difficulty making a gp appointment"

We are not regular users of the local gp practice (Guidepost Medical Centre). My wife just phoned up to make an appointment. She was told there isn't any and they are full up next week. When asked how to make an appointment was told to ring up each morning to see if can fit in that day due to a cancellation. She could hear a conversation in the background, then someone said to open the appointments screen and my wife was given an appointment. This all sounds very suspicious that there are no appointments, yet it seems that there are. Also why would you have to ring each day to see if there is a cancellation for that day.