The sound is quite a high squeal which happens on high revs when accelerating or when in Park and just revving.
First post of call is the manifold stud. Haydn Callow has posted a helpful pic with an arrow pointing where it is and I've had a look tonight and still not 100% sure what I'm looking for.

This is what I've got:



Hopefully the pics are clear enough. Any help on this would be appreciated, even just to confirm whether it is the stud or not.
Also, I was also wondering how the stud becomes sheared in the first place? Is it a slow build up or a quick kill!

Andrew