After reinstalling the engine and taking her out for the first drive(I hadnt driven the car befiore this point) I was greeted with a horendous front suspension knock that was present on both sides , looked at all the arms , bushes and ball joints and all looked in good condition and where pretty new.After a bit of investigation I came across a few posts/vidoes of people with C5 A6s which had a knock but they where struggling to find out what was causing it , a few of them ended up removing the front strut assembly to invstigate further and they seem to find taht the top strut mount bush had failed and after replecemnt the knock stopped.
So after my initial investigations on the car looking ike trhe arms where not that old I thiought I may as well check the top strut mount , and they were absolutly destroyed.
I think the H&R coilovers may have caused the failure as they are not very soft , with the stiffness transferring a lot of the load to the top mount.
They had split in two the rubber had failed completely , the photo above doesnt it justice.
While I was there I also found that the top rear suspention arm had a split bush and a knackered ball joint , from my intial testing I couldnt see the bush properly as its tucked right in to the wheel well and I must admit the ball joint felt OK when it was installed but removed from the car the ball joint was shot.
So releced the top mount and top rear arms on both sides and the front end is transformed , how long they will last with the combination of H&Rs and the amount of speed bumps around where I live is questionable but at the moment it feels fantastic compared to the first drive.
If you are having suspension noises and you cant find out where its coming from , dont forget to check top mount , only issue is theres no real way to check them without removing strut but its not a mega difficult job (unless the pich bolts is stuck!!!)I was lucky that my pinch bolts had been replaced at some point and came out without issue.