Well you could do a couple of crops here; one almost as shot, or keep just the main subject, in (say) a square crop.
If you retain the birds on the left, I would locally tone down the bright white chest to below the level of the main subject's chest, but don't over do it, or it'll look wrong.
I probably favour a tighter crop - to get more bird in the frame compared to background.
A small increase in overall exposure could also be done, as suggested by Bobo and Muriel.
For the record, the EXIF data says; Canon EOS 7D, EF70-300mm f/4-5.6L IS USM at 300 mm; Manual exposure, 1/1,600 sec, f/5.6, ISO 320.
Well It took a while, but here is my finished image, thanks again for all the advice.
I went for the tighter crop in the end, and a slight adjustment to the exposure. I also had a go at lightening a couple of dark patches in the background, and tried to sharpen the feathers a little, all of which was a bit of a learning curve for me as I haven't really used photoshop much at all.
As Dave mentioned, you did exceptionally well with your learning curve. Your second version is comparable to that of a far more seasoned post-processor. Congratulations!