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I actually think it's a really cool feature.
This. Keep it!
It's not an original feature, but it does have a lot of character. Do you really want some bland fireplace like everyone else has got instead? That's mad.
I would do the rest of the room very minimal, modern and tasteful, paint it all white and have that as the big character feature in the room. Get that light fitting inside working as well because it would look even cooler lit from behind, OR have a retractable TV or projector screen come down from inside the cavity behind the mantle/lintel. Then you wouldn't have to look at your ugly TV when you're not watching it.
I actually think it's a really cool feature.
I'd probably still get rid of it, but I'd feel bad getting rid of something that's genuinely quite unique.