[Red Herring]

My general advice is that if you have come up behind another vehicle it tends to suggest that your average speed is higher than theirs, so if a safe and appropriate opportunity to pass arises then it would not be unreasonable to expect you to take it. If you don't take it I would be looking more at the reasons you didn't go rather than simply telling you that you should have gone. Is it that you saw danger where there wasn't any, perhaps you lack some confidence in what you do see, or perhaps you just weren't looking for the right information. Certainly on an IAM test you would be unlikely to be failed for missing a single overtake, but if it was a general trait you would be unlikely to make the expected standard. Progress is not about going fast, it's about processing information swiftly which allows you to maintain speed where appropriate.