How do i fix the door closing mechanism.Hotpoint TDL 30 Tumble Dryer?

Hello can you help, the door on my Hotpoint TDL 30 will not click shut when closed. the door itself is fine, it is the mechanism inside the body of the Tumble dryer. The inside of the mechanism still moves and i can wedge the door shut and still use it.
Is it an easy job or will i have to call someone out.??
Thanks for reading.
Ian