My dad has been an electrical contractor for 40 years but has recently given up in favour of odd jobs. He just couldnt face having to pay to be trained in part p requirements by people who know a damn sight less than him!
In his words 'i have forgotten more than they will ever know' meaning that in this day and age the skills he was taught are getting lost!
Cant say i blame him!
Sounds like my Dad. Chartered engineer, degree in electrical and electronic engineering, fellow of the IET and 40+ years experience in hardware development, who has been reduced to illegally re-wiring his own house. 
Kevin
I did my daughters bedroom. we live in a 30's house which has been updated but I wanted a lot of sockets, so I did it, then discovered a scource of Red and Black T&E, anyway thinking to the future it is not connected to any of the rest of the house so when she gets older and the music gets too loud I can trip all but one socket in the room from downstairs.
Lol, fear not.
I doubt any of you have broken any rules (note, they are only rules, the most they can
practicaly do is force you to get the install tested and signed off!). You of cource have an alternative option of having your work tested as part of a 10 year inspection and present the results to building control (who will charge a fee) to sign off and you HAVE then met all the requirements!
Part P is a typical set of naff rules which you can drive a bus through (just like the gas regs!) and to put it simply, you are permitted to carry out small jobs i.e. adding a socket, repair, replacement etc.
And as a certain building control inspector said to me, if you carry out a large number of small jobs you get a large job done.....and you wont have done anything wrong
Just be wary of kitchen and bathroom installs.