Thanks everyone for your suggestions so far!
The staging ideas are actually really good, as me being a typical guy, so long as the empty pizza boxes are beer bottles are put away, I thought it was staged!
But I am going to try those suggestions for sure and post another shot once that's all done. The straightening issue I think can be addressed without trouble. The only thing that will be a problem for me is adding more flashes, as I only have the one and am concerned about trying to mix sunlight, incandescent light and my flash and the white balance issues that will adopt themselves into the shot. I need to get a gel filter for my flash so that I can at least match its white balance with any incandescent lighting. The sun is also going to be streaming through the windows very shortly so may need to wait until tomorrow to try this again.
Thanks again everyone!
Cheers!