Chris KA. We had the knocking sound when the car was stationary and put into D or R but not when it was in P with just the engine ticking over. The knocking also tended to stop once the car started moving up to speed. After some investigation we found that as the revs lowered when put into D or R it was causing the air intake pipe to vibrate and knock against the engine. It has been zip tied to the cable loom just behind it and the knocking has now stopped. Hopefully yours may be as simple.