Pre-cast flue .. or not

[Grinning Grandad]

Hello, not sure if this should be in this section or building. We had our old gas fire removed so we could see what was behind and what options we had for a new fire (ideally something inside the hole with no hearth). When the gas engineer removed the fire he said that it was pre-cast flue and we would be limited with our options. Whilst researching the options (and what a pre cast flue actually was) I noticed that we shouldn't have a chimney - which we do. Also there used to be a back boiler. When I pointed this out to the engineer he thinks that maybe it's not a pre-cast flue after all and it's just been built up like one. I'm not sure what do next as I don't want to start removing the bricks if it is pre-cast. Any advice welcomed.

 

[petit_pablo]

What does the actual chimney look like from below?
Catchment space doesnt look like a precast.

 

[Grinning Grandad]

Thanks for you reply, do you mean below from outside?
The dimensions of the space are 380mm wide, 580mm high and 445mm deep. The flue is 5"

 

[petit_pablo]

I meant from inside looking up the chimney but if its 5" round no matter it isnt a precast chimney. Precast chimneys look like your looking up the inside of a load of oblong breeze blocks only the are narrower. Roughly 185cm wide by 90cm deep depending on age

 

[Grinning Grandad]

Sorry about that, does this help... The ducting goes straight up about a foot then curves backwards.

 

[FiremanT]

Is your house poured concrete

 

[Grinning Grandad]

No, it's not poured concrete. About 15 years ago (before I came on the scene) my wife had an old gas fire and back boiler removed and a combi boiler installed. She seems to recall seeing a bigger opening but doesn't remember anything being built up to accommodate the new fire. However around the opening is very rough plastering and there is no outlet in the space for any pipes (entry point seen on the photo) and also the plumber removed a back boiler somehow. Is it looking like this isn't a pre-cast flue and it's just been built up to accommodate the fitted fire?