Nick, it is identical to mine, and my car came out ok
, so there is light at the end of the tunnel!!
Make up some little brackets to hold it all together, don't worry about screw holes as you can fill them after. Do the side and top separately as it is easier to align and you are working with smaller bits. It will look a bit like Frankenstein's monster to begin with while you are bonding it all together, but when you remove the brackets after a couple of days, and stand back, it will look ace!
Get yourself a flexible sander and velcro sandpaper and the filling will be a whole lot easier!
Good luck, and feel free to ask any questions!