Ok so let me start by saying this noise has been there since i got the car new , but im lazy so never bothered about it till now 

it will happen maybe once a day going over a road that has both negative and positive camber and sounds like its coming from the back end 

its not a knocking more like a graunch noise , does it once then thats it you wont hear it again 

 

anyone had any problems or issues with any bits of suspension that i can check out ?

thanks Mark.

Yes i have an estate and it does it then i dont hear it for a while, it does it in exactaly the same circumstances to.

My old Passat estate did that when laden.

It was the standard rear mudflaps scraping when the road was deformed.

Current Combi has been ok.

Its a 'feature' of the torsion beam rear suspension. Basically the back wheels are linked together by a beam, its cheaper to make, but noisier and the handling isn't as good as independent suspension.