Yeah, I'm waiting on the tensioner from Mark also, before I look into it any further.
(Good riding weather here ATM)
I recorded a video of the noise, but surprisingly you can't hear the clattering noise on the video.
Anyway I have a before video.
If the after (new tensioner) video shows a difference, I will post them.
I will try and do a better before video, before pulling down, I suspect the exhaust is making the cameras auto volume attenuate the chain noise.