Chainline noise - videos/photo

I know there are a load of chainline threads and i know how to go about shifting the chainring over using spacers but I'm not entirely convinced that all the noise coming from my bike is from the chainline, I think the sprocket may be part of the problem too. To cut a long story short here's what happened:

1. I wanted to lower my gear to go up the massive hill home
   
2. Bought 20t sprocket, went to fit it but cheap hub thread was stripped.
   
3. Bought System-Ex hub, fitted 20t now the bike sounds like a jet engine!
   
   

The chainline really doesn't look far enough out to generate the amount of noise coming from the back, do you think the 20t may be all out of shape or something?

Check out this pic:

Does it look out by a mile, I've spent so long looking at it I'm going blind.

Also a couple of videos with the noise:
http://gallery.me.com/tfrancis#100104/chainline-1
http://gallery.me.com/tfrancis#100104/chainline-2

Thanks for any help,
roon
http://www.fixedgearwales.co.uk