Defo new chain time then.

What do you reckon the notch type feeling I'm hearing/feeling could be that goes away when the clutch lever is pulled in?

I took a video though it's not very good in terms of highlighting the noise.
I pulled the clutch in at around 16/17 secs into the video.

https://youtu.be/W4mmQvbWeIU

Would get the cover off and check the clutch theres a guide and youtube video by a forum member on replacing clutch plates .
Check the small outer pushrod bearing the clutch nut is tight and as i said before get hold of the entire assembly for movement in the basket and shaft itself .
If thats ok undo the nut and remove the plates look for wear or burrs in the basket itself where the plates sit.