Whilst driving around a fairly sharp left hand corner there is a knocking sound from the front end. but ONLY when i turn left with a bit of speed behind me, dooes this sound like a broken engine mount or something to to with the steering/suspension??
Check the swaybar link pins first. These are more common to wear the bushes than an engine mount going.
You cannot really break the engine mounts - they normally just sag until the engine touches the K-frame.
probably the mount...as mentioned they sag and make a metallic rattle on hard/medium turns but the nature of these things means it could be any of the other causes too, do the mounts first then try the others