Jonathan, this is really nice! You did a wonderful job using fill flash but not having it LOOK like you used fill flash! The DF is in great focus - might want to try a little selective focusing on the eye - but the rest of him is crisp and highly detailed. Nice composition and excellent BG. You might think about giving it a bit more room at the top so that top piece of plant/flower has a bit more room, but it's very nice as presented.
Great image, the blues and the warm tone in the perch is just brilliant Jon. Sharpness looks good.
A few fine points:
Taking 1 or 2 steps to the right would really help place the Dfly parallel to the sensor as it is now it is slightly angled away. You can see this since we can see the back of the head.
I used this same set up for years so I can give you some advice to fine tune your results. Remember the BG is controlled by the camera Exp Comp. So I would have not dialed in minus comp, I would have went to plus 2/3rds comp to prevent noise and lighten the tone to a med gray. Raise the ISO to bring down the noise? More exposure with a higher ISO but will keep noise lower than a darker tone at a lower ISO setting.
The flash comp controls the tone of the subject so I wouldn't lower it here as your setting is fine, but I would have placed a diffuser, even a sheet of paper or facial tissue, over the 550ex to tone down the harness to eliminate the 'flashed' look.
Thank you very much everyone for your comments, Robert I will take your suggestions regards ISO & compensation on board. BTW sorry for late reply - my computer threw a wobbler but it is OK now.
Jon