Gavo mate, I really feel for you here. This has been a nightmare for you.
So I have been away for a few days with work etc and come back on here expecting you to have gotten to the bottom of this issue. I got excited for a second then thought well strut top mounts does not make sense. Magnet picked up on this straight away too, it really does not make sense at all.
You can do a basic test on the strut top mounts by the help of a friend. Park the car on grass, wetter the better. Don't have the engine on!! Get some one to turn the steering wheel from lock to lock while you have the bonnet up and both listen and feel the strut mounting point. The offending side will make a noise and maybe even clunk at either full lock. Hope this helps.
Going 0mph or 100mph won't make a difference to the noise of the strut top mounts and I am so sure you say that you can hear. Noise when traveling now, whether you are turning or not?
However, if it does indeed turn out to be these mounts then please accept my sincere appologies for offering my advice incorrectly. The dangers of reading and assuming we know what's wrong without actually driving someone's car.
keep us informed though mate.