Another update on my situation. To be clear, the reading of 378ng/100ml put my reading at almost twice excessive consumption - approximately 8 (Australian) standard drinks every day for the last month. That's approximately 240 standard drinks in the month before the PEth test, when I had actually consumed a total of 18 standard drinks in the 5 weeks running up to the test, with zero alcohol consumed for 12 days before the day.

When I received the results, I was shocked so I arranged a CDT test and got it done that day (24 March), which was 8 days after the PEth test. I had another CDT test 6 days later (30 March). I received the results of the tests CDT tests today. Both came in at 0.3%, which is consistent with the amount of alcohol I have actually consumed. I've sent it to the lawyer$. We'll see what happens...