Update:

Hello, I have internet again!  I feel like I've been offline for weeks, even though it's only been a few days.  Last week was a bit gruelling, but everything has been moved from the old flat to the new flat.  I never thought I'd say this, but thank God we don't have two homes anymore!  Everything is disorganised, and probably will be for a good while yet, because I started a new job today and don't have much spare time on my hands.  Still, here's some photos of what we've temporarily done with the fireplace:

Before...

... and after!

The blank tile that's covering what used to be the open fire is very plain, and we will hopefully cover it at some point with a poster or maybe a large piece of patterned tile that would compliment the original tiling on the hearth.

Excuse the clutter, it won't always be like that!  As you can see, we've hung a mirror that I already had, but it isn't really big enough and looks a bit silly on its own...  I think I'm going to try and get hold of a few smaller, cheap mirrors in different colours and shapes and hang them around this one as a sort of collage.  I was inspired by this photo I found whilst browsing Pinterest:

It would reflect a lot of light into the room, and there is certainly a lot of empty wall space to be filled in this flat!