Thanks for the comments everyone. It hadn't even crossed my mind that the man might not stand out from the tree, because he always sprang out of the background for me, from the moment I saw him hanging there. Great feedback, thank you.
Roger, I thought about cloning out the string, and in some of the pictures it is more obvious than others, but I wanted to make it clear that I had recorded what is there in camera, not dropped the man in with Photoshop. I've only thought since that I could have been true to that but hidden the string if I'd spent a bit longer composing the shots.
There is no HDR here, all I did was play around with the sliders in the raw converter to recover a couple of blown highlights in the metal and turned up the colour temperature. I'd used fill-in flash (set to -1 stop) because although the top of the tree was in strong sunlight, down where the sculpture was hanging was in shade, and it seems to have balanced the tones pretty well. Perhaps all of that comes to the same thing as HDR.
Thanks again!