We have a sixties house with the chimney breast built on the outside. We want to move the fireplace 6 foot over in the lounge as we are extending it.

Hi Foxglove, If you are wanting to move the fireplace over and still have it as a working fire going six feet may well cause you problems if you are planning to make use of the old chimney. You would need to think about supporting the chimney stack upstairs, and also by moving it over that far you would have one heck of a lengthy and shallow bend to connect the two together. Difficult to say whether it could be made to work or not without seeing it. You could remove the stack completely and use a new flue directly above the newly positioned chimney stack?

You may have to remove the chimney stack altogether as nothing would be supporting it. Or you could turn it onto the other wall if possible. Hard to say without seeing it.