Hey there Anthony, what did you end up doing with this space? Bit of a tricky space!

hi there khiara, I know this is an old post but just wondering did you ever try turboheat and if you did how did you find it? thank you :)

Depending on your house style and how it would work with the 3 different measurements, you could look at doing a herringbone style pattern for example:

all heaters and stoves should have very specific installation instructions including distance above the stove to any mantlepiece and i suggest you start with advice from local suppliers and then confirm with specific written instructions from each manufacturer that you can usually find on line...There are a number of heaters that have wood fires that are designed to be inbuilt in a purpose made wooden frame so hopefully this can be done inside your opening