Another thought would be to balance it visually by adding a false display of wood stacked up in a recess. A mantel shelf could then span the entire width providing a visual divide. The upper portion could take an art piece or mirror across the section with out looking unbalanced.

Hello! We have decided to get a corner gas fireplace. However, I am finding it difficult to find distributers in the UK and unsure as to what brands are quality. If anyone has any experience with owning one or knows about a few brands I can explore please help.

I see, not an easy one. The first thing is to establish what is behind and how the original fireplace looks like. You may try to have a peak behind or just ask neighbours how theirs look like and whether it is the original. If you like it and it has been covered by the previous owners, you can just renovate it. Otherwise you can get the marble, it looks quite neutral and just rearrange around. I would recommend that you do not rush it. So discuss with your builders how the floor can be laid down and still accommodating for further adjustment later.

Yes you can. Get a heat resistant paint in a paint shop