My own Feral is not yet 2 years old ...
Ha !
An email to Vauxhall UK elicited the response:
The diagnostic fee will also be meet by the customer until the cause of the fault is found. If the fault to the unit is due to a failure of part, or a breakdown of a part over time, the diagnostic fee would be reimbursed to y ou. The fault would have to be due to miss-use, or caused by yourself for d iagnostic fee to be chargeable.
So if they cannot find a fault (it is intermittent), the owner is left with the diagnostic fee, which is unavoidable I suppose.
Since the warranty runs out in July, I think I will just have to fix it mys elf when it gets bad enough. It has actually been OK for the last few inser tions of the disk "The Wheels On The Bus" !
Simon.