Turns out that this examination is purely voluntary and is offered by the company as a benefit. If this benefit is accepted, it will only be done once in Oz. I can't quite fathom why doing another test is a benefit but am not going to bother too much about it for now. Got lots of other pressing things to address!
Hubby is going to love this ... something else new in today ... he has to do another medical examination! He already did one while he was in Oz at the company's request (which included a SUPERVISED urine test). We have to do the usual Immigration Department medicals and now he also has to do an International SOS one to 'ensure that your health is appropriate for the assignment'. Included in this is the required immunisations for the location which applies to the whole family.