I know Part P "comes into effect" on January 1 but can someone clarify what
this actually means... eg if I start rewiring a house before January 1 (ie
very shortly, which is my intention) and it's not going to be complete by
then, do I have to rush off to the council on 2 Jan and put in a building
regs notice?

If not, how long I have I got to complete the project, and would I need some
form of proof (if so what?) as to when I started the work?

(Sorry I know this has been covered here before but I can't find it amidst
the plethora a Part P posts!)

Thanks
David