For both exhaust manifolds RAVE says:
- Release exhaust pipe from front rubber mountings.
- Remove two bolts securing exhaust pipe to front support bracket.
- Remove four nuts securing front pipe flanges to exhaust manifolds. Release front pipe from flanges and move aside.
Next it says that the four nuts securing each manifold to its cylinder head can be removed.
Is that any help? Workshop manuals rarely give advice on how to reach inaccessible fasteners. I'm afraid that it's up to you to devise a method which might involve buying an appropriate tool.
Simon