How can I be certain that the sound I get under load is the passenger side exhaust manifold?

Can't see or hear any leaks when stationary, even when rev'ed hard. Can't see any evidence of a leak either.

I don't have the shield / insulation on the downpipe anymore - it fell apart. Would this make a similar sound to an exhaust leak - but only under load?

Will do, not sure I'm up to changing the passenger side manifold gasket.

Had a go this weekend (without moving the engine) and rounded off a manifold nut. Mind you not moving the engine wasn't the cause - the nut/stud was seized. On the plus side at least it didn't shear.

If it is the manifold, and bearing in mind I have at least one seized stud, is it engine out or head off?

Head off - seems like a mamouth task with plenty of scope for error. Head bolts, angle torquing, camshafts off etc.

Engine out - no hoist and no air con emptying / refilling facilities

I was wondering what the outcome of your leak was - it seems you were most fortunate

I've had a feel round there - but can't find anything - b*gger!

I had a bloody good go at the weekend. The problem is the seized stud is the one nearest the ABS modulator. The nut has rounded off. There's no room to hammer a socket on and I suspect the stud will shear before the nut or stud comes out. If it does and it's flush with the head I'm scuppered. The car won't be drivable and the engine will need to come out to drill the stud out.

BTW this forum software does strange things with some of the words I'm using......