Indeed. I am the only skilled person they have. I have confirmed I am happy to work with 600V given that I have done mains work to my knowledge this is as dangerous as in, "it kills". We do vehicle stuff so assuming no earthing in the vehicle there would be no earthing in the test. Should we temporarily earth any metal body and use a bender to protect from any faults on the DC side like an RCCD would do on the AC side?
I am surprised you ask this question!
That means no person in your company has basic training with this kind of power?
There are courses offered now for the car repair business for the correct handling of electric vehicle safety in the repair shop. In Germany, a car repair shop is not allowed to work on electric vehicles, without having done this safety course. They are not even allowed to repair a bumper!
I highly recommend such safety course before starting work on this project!