Old fireplace, making a feature: Venting needs for chimney?

[H0ckeynut]

In the back room of my terrace house we had an old back boiler with fire in front. This has been removed and the (presumably) stainless steel flue has been cut in this recess. I plan to use this opening as a feature by plaster boarding the opening (obviously covering over where the flue comes down) and doing the obligatory "put a big candle in it" for now...

I'm trying to ascertain what venting the chimney or the stainless steel flue would then need to prevent issues in the future. Can anyone help advise me on this?

Behind this location is a passageway which I could potentially vent into if it's needed.

Thanks,
David

 

[H0ckeynut]

Can anyone advise on this? Here are some pics to help visualise what I'm trying to explain. Behind this is a passageway.

Do I just need to remove a regular brick from the back (in the alleyway) that provdes air to the main chimney breast?
Do I need to vent that old flue too?


Pics