From what you say, and if you are OK with spannering, then £500 should easily sort the car into MOT shape. Forget the sunroof fault - it's only a "nice to have" unless it's fully open and won't close!! Alloys are cosmetic too.
Don't forget you may need the space, and once a wheel or two is gone, or a suspension part, then it's immobile and can't be towed, or even dragged on to a low loader. The higher value bits are the larger ones that need more getting out, and what do you do with a static lump with no engine/box or suspension and a return on your time and parts of £1500??? Pay £50-£100 for it to be taken away?
If you want value from it, sort the suspension, strip it out and use it as a track day car!!