Metal chimney

[LostInTheUnderflow]

I have a problem with my fireplace where the metal inner is not connected properly to the fire. See here:

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• LostInTheUnderflow
• 3 Mar 2015
• 1

I managed to get in behind the fireplace and found this:

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• LostInTheUnderflow
• 3 Mar 2015
• 1

Untitled

• LostInTheUnderflow
• 3 Mar 2015
• 1

My question is how do I dismantle the outer pipe so that I can fix the inner pipe?

Any help greatly appreciated.