Julian,
I'm not an AME, but I am a doctor, and you are absolutely correct. One of the main reasons for asking about family history, performing blood tests for lipids, measuring blood pressure, asking about smoking and calculating BMI is to build a picture of cardiovascular risk. There are very few clinical signs on examination which will alert a clinician to the presence of coronary disease, and in many cases there will be none. In the absence of a history of symptoms (angina, pains in the legs after exertion etc), adverse risk factors or a positive family history, it would be difficult to justify more invasive investigations. These may include formal angiography, which carries a complication risk, or coronary CT, which is associated with radiation exposure. Therefore in someone who is otherwise low risk, the risk-benefit ratio would not be in favour of performing further investigations.
This case is tragic, and the natural response of anyone grieving for this man will be to ask questions. The class 1 medicals are quite prescriptive and standardised, so it is difficult to see how anything could have been handled differently, or how this sad outcome prevented.
Broomstick