I played with it for awhile, however what you have come down to is reconstructing the image from what is available and ethically, I don't think that's quite right. You can fix the flare on the right, but 'redoing' the image and fundamentally changing in a computer is the stuff of something other than 'straight photography.' Instead, think of it as a lesson learned, or perhaps think of your work as computer work instead of photography? Tough questions for which there are no clear answers.
Ethical shmethical. If you're shooting for a client, and they ask for something specific, do you think they care what method you use? Do you really think they want it as in-camera as you can get it? I would think that as long as you provide a service and produce a result that they ask for, then you should use whatever methods you have available to you.
Perfect example: Do you think this client cared whether or not this could be done in the camera or in the computer?? I don't.