Lighting & Sockets?

Not going to put in two catagories so here goes.

Although not an electrician but a competent DIYer I want to replace the cable on the lights and sockets in my garage. Will any of this work involve Part P 'notifiable work' directive/s. Nothing added just replacement of cables. And does any part of part P directives insist that all cable should be either capped on in box/round conduit?
Consumer unit is MCB type.
Many thanks in anticipation.