My manager isn't happy with it!
Is there a way I can make the main image the top layer, so the other images with the flail moved are less visible?
Do I need to cut out the top image or something?
I think you are making it too complicated. This is very quick and dirty, because the image size is too small to make a decent selection, but even if you want to keep the background. select just the extended bit from each side, and copy to layers _below_ the central object. Then reduce opacity to get the desired effect, which seems to be to demonstrate the movable front section.

It pains me to see you struggle with this, and I especially hate to see a fellow graphics person getting grief from their manager, so if you are really having trouble getting it exactly right, upload the individual images at a decent resolution (or email - my email address is easy to find), and either myself, or someone else will fix it for you, and you can tell the boss that you did it. 