So after a bit of playing around to learn how to use the new features in Lightroom 4, I think the image is better balanced now. I have removed the barrel distortion. Used the rotate and vertical adjustments using the plinth in the centre of the image and the doorway as guides.
I think my original edit was too bright and I lost too much in the highlights. I have changed the colour balance and brought up the shadows a bit more so there is more detail in the couple in the foreground. By reducing the highlight adjustment there is now more detail in the ceiling. I think this is a better adjustment.
If I compare it with the previous version: