Only certain trades are entitled to overalls and other PPE. Has the sqn ldr, or any other B class driver undergone the appropriate car cleaning course?
Have the hazards associated with getting up close and personal with that type of car been pointed out?
MT driving rules also apply.
His working day starts at the time he/she picks up the car. It ends after 1 hours (I think) hard limits. He may drive for up to 9 hours with statutory breaks.
Clearly if the call to wash the car came after 11 hours duty he could state that he was now 'in-rest' and would attend to the task at the next available time on duty. If he agreed to wash the car, MT would be required to drive the car to the wash area for him.
I am not making this up but H&S and EP are mandatory and you would be crucified for breaching their rules. Use their rules to your advantage.