Vince,
Your account is an instructive illustration of the discrepancies between what really happened and what people imagined to happen.
It seems there is a discrepancy between the margin you thought you had and the margin you really had. That is a common story and I can contribute at least one recent example of my own.
The engine stopped, likely because of fuel feed, imbalance or unusable quantity problems. It sounds like you were down to half an hour's fuel which to me is time to land ASAP. That last half hour's worth of usable fuel is test pilot territory in my book. I'd want to be high up over a long runway with lots of recent power off landing experience in type before exploring fuel feed at low tank levels. Usually the test pilot has an auxiliary tank that he can switch to when the engine can't get any more from the tank under test
Manufacturers tend to maximise their performance numbers and minimise unusable fuel quantities. In so doing, their test pilots fly very precisely to get the best numbers. You will not get those numbers yourself unless you fly exactly as well as the test pilots.
It looks like the altitude Dundee ATC assigned you had you too low for options or restarting if the engine stopped. That is life, but if I were concerned about fuel or the engine, I would want to be as high as possible and let ATC know that.