How do you tighten the rear bumper?

[paddy wright]

Washed my car last night and the bumber seems slightly lose on left hand side. Any help please?

 

[powerontap]

Same problem with mine here;
http://www.z4-forum.com/forum/viewtopic.php?f=3&t=4826

Believe we need to replace the rear support where it snaps in.

 

[paddy wright]

thanks for your help!