The 'knock' feels like it's emanating from around the area beneath the clutch pedal. As mentioned, since changing the dampers, lower control arms and drop links the 'knock' is far less noticeable ie. it happens far less frequently, not that it's quieter. The garage did assure me that the top mounts were fine, could they have missed something whilst inspecting them? Would a faulty top mount cause a 'knock' from beneath the clutch pedal? Might it be the front sway bar bushes as these are around the area beneath the clutch pedal?