In the loft, the flue looks like it's made out of metal. I'm not sure
if the metal goes down to the fire, or if it's something else.

The hot stack is getting too much heat. The wall above the fire
surround has paint blistering off the plaster. The room upstairs has a
gloss skirting board that's too hot to touch. It seems like a fire
waiting to happen.

I've been having a chat with a few people at work, and it seems like
the air vent at the top of the fire is too big. The vent on my fire is
about A4 in size. Most people's fires seem to have smaller vents. I
think the bigger the vent, the more heat is getting chucked up the
flue, rather than into the room.

Does that make sense?