Canopies for smaller fireplaces ("full width canopies")
The "draw" on smaller fireplaces can often be improved
by fitting a full width canopy, which helps reduce the
fireplace opening to an area more compatible with the
flue size.
If your fireplace smokes consistently, you can test to see one of these might
help you comparatively easily by lighting a small fire and holding or taping a
board or piece of tinfoil across the top of the opening, and seeing how low
you have to go before it starts to draw properly.
They can be made either straight as above, or curved as to the right...
I normally finish them with 12mm round bar safe edge at the bottom.

Typical prices from £80.00 - £200.00 to make, £90.00 - £150.00 to fit.