Don't confuse the existence of the Part P amendment with the administration of the scheme. You could, for example, have an arrangement where you pay £50 a year to register with your local Building Control, after proving you are competent and showing certificates etc. You then simply send them a letter whenever you start a notifiable job. They could choose to inspect any of your jobs at short notice, and being local they would soon get to know who is competent and who isn't. This system could be financed in different ways, such as a small increase on VAT for electrical fittings; this would have the added benefit (from a contractors point of view) of discouraging DIY electrical work.
My feeling is that Part P is now seen as inevitable as death or taxes, but actually now is a good time to put pressure on to get it changed or scrapped. The problem is that the British working class is too supine to take any action; easier to let off steam on a forum like this than email an MP! (Not referring to you by the way, just a general remark!)