I have owned a 2006 Vauxhall Corsa from new and it now has just short of 51,000 miles on the clock. In the last year I have experienced gear selection issues and it seems to be getting worse. It occurs when changing down from fourth into third, third into second and, very occasionally, when selecting first from neutral. It feels as if the gate on the gear is completely closed, as the gear will not select and only putting the car in neutral and trying again will allow the gear to eventually select.

My local Vauxhall dealer has looked at the car and has ruled out the commonly-known issue of the gear linkage as they say it is not worn. They have also ruled out the clutch, as they have checked the air in the system. Can you help?