Just buy the parts (front/rear suspension, wheels) and say they were from the original car? They're highly unlikely to check, and if they're bought with cash there's no way of the DVLA finding out.
its not up to dvla to prove anything when you register it they will expect you to prove it, there inspectors will crawl over every major component from the shell to the back axle looking for numbers if they don't find the evidence you may lose the vehicle or at best gain the old q plate designation.
at worse you sell the document or vehicle , someone buys it in good faith and then somewhere along the line the vehicle gets stopped and checked. they don't like what they find and send it for a full inspection and then a whole can of worms is opened.
in the old days i used to do a lot of rebuilds reshells, q plating etc and the onus is always on you to prove everything, it can take months and years of going back and forwards , if you get your ducks all lined up it can be easy but on the info you gave i very much doubt it .
under the old system you had to gain points per original item, and bodyshell was important, using anything other than a brand new shell with official paperwork was automatic q plate .