On test:Cockpit checks
It would be normal on your driving test to have driven to the test center. So as such your car should be properly set up and adjusted. At the beginning of the test remember your pre start checks. Handbrake then neutral.
Most modern cars will need the clutch to be pushed down before starting. The idea of this is as a safety precaution with small children. They may be able to turn the key but not to be able to push the clutch down.
Some modern cars and older ones will be able to be started in gear. This could be a problem if it causes the car to go shooting forward. This could be quite dangerous.
Having the car properly set up and adjust for the driver means it can be operated safely. Not to have done so correctly will generate faults under use of controls or mirrors.
If the car cannot be adjusted due to mechanical problems and the examiner does not think you can safely operate it. It will not be going out on test and you will have failed before starting.