Hello all,
Noticed a funny droning/vibrating/scraping noise coming from the cambelt area of my car a few weeks ago. Pushing down on the cambelt cover seemed to reduce/stop the noise... I pulled the top half of the cover off and there appears to be some damage to one edge of the belt:

Does that needs replacing asap or should it be ok? The 'unscathed' bit is still over 22mm wide (mentions something about this in the Haynes I have).
My thinking is that the bolt that holds the lower half in place has fallen out, since it wasn't there when I checked! (Have recently fitted a fresh one with some threadlock)

My thinking is that the bolt may have fallen out and is now sitting in the bottom half of the cambelt cover, catching against the belt - does that sound about right?
If so, how do I go about getting the bottom half off to check?

I would prefer not to have to disturb anything vital if poss since I'm not super-experienced with this sort of thing, but it looks like the aux belts need to come off to give me enough space to get the cover off. I've noticed one bolt at the very bottom rear corner of the cover (nearest the driver) and another one facing towards the headlight. Any others I need to be aware of?
One last thing - how much twist should I be able to get in the cambelt when it's at correct tension? The Haynes mentions 45 deg in one place, 90 deg in the other, then says the ABF engine (which is the one I have) needs to go to the dealers for checking with a tension meter!
Thanks in advance for any help!
Adam