Recently bought a Bentley GT 2004, 100 kmiles. Knocking noise coming from rear left (I think) when going over bumps/speed ramps - seems to be when load comes off. What's the most likely cause?? - antiroll bar fixing, suspension mounting, air damper? Anything that can be inspected from underside? Last Bentley service with previous owner was 12 months ago (6000 miles ago) so car has been cared for (11 Bentley stamps). Other than that everything great. Thanks for advice. Cheers, Paul