Hi Stephen
Yes we allow 45 mins for initial evaluation.
We have tried to give a time to find a fix
however it has not worked.

We now say you are paying us to carry tests out on the vehicle for each error code where faults will then be found with this procedure.
Returned errors first and then intermittent if they return whilst with us or'now monitor vehicle and check light'if the car is returned to customer with int faults not looked at.

This seems to protect us from all the issues of poor and high miles/abused vehicles and intermittent faults.

HTH Simon