Blocking Old Brick Chimney

Hi all

Firstly, I wish I could edit the title to reflect the correct spelling of ‘Chimney’.

I’m hoping this is the most appropriate forum to post in given it’s sort of related to brickwork!

We’re in the process of renovating the lounge of our mid-60s double brick Perth property. The lounge has an old oil burner fireplace that has been inserted into a traditional open pit fireplace. There’s a flue from the oil burner up the chimney and a flue cap at the top surrounded by lots of mortar holding it in place.

I want to remove the ugly dark yellow coloured oil burner from the open pit fireplace so that there isn’t an eye-sore in the centre of the room’s main wall. My intention was to insert a chimney balloon inside, then cap the exterior by removing the flue cap and surrounding mortar followed by some sort of Zincalume/Colourbond flashing. Either that or some thick rebar, flashing then covered with mortar.

Is there a better way to do this? I’ve seen some suggestions on this forum of using a concrete paver with liquid nails. I’d probably want some masonry fixings as well. Any other ideas?

Thanks!