I wish to paint the interior of a very large fireplace which accommodates a large wood-burner. I should appreciate your advice - please
Assuming the walls to be painted are cement based plaster, brick or a mineral board, they are bare, clean, dry, sound and prepared as detailed in the technical data sheet you could consider Tikkurila Muuri.
This can withstand 300°C in the white colour or 180°C with a tinted colour option.