Bit difficult to explain this one but before I revisit the dealers does this ring any bells with anyone?

Occasionally after reversing the car and then selecting drive, a short time afterwards (maybe 5secs) there is a loud cracking sound from the nearside of the car. 

Because I regularly start my journeys by reversing out of a parking space I originally thought perhaps the wing mirror was getting stuck whilst unfolding then snapping into place but having checked its not that. 

Edited 27 March, 20233 yr by Craigster

Turned out it was an 'arm' that adjusts the air recirculation vents. Dash out job to replace the part and it comes in two varieties so visit one to identify it and visit two to fit it once ordered and in stock. Didn't sound like it was the first time they had to replace one.