problem mostly is people are not aware of part p (or even wiring regulations!)There is loads of DIYers (like Apache) who do what they can to do the work safely, read up a bit on what there doing etc, and then are the others who just bodge it (like that badger) . part P isnt doing anything to stop either from DIY, but we all know who's house isnt gonna burn down/end up with someone dead
Even if part p completely banned anyone from DIY, other than registered sparks it still wouldnt work and would make 'unknown' work even worse than it currently is. get rid of part p and things would most likely be safer