The little that I know is based on my last car and that of a colleague. Mine was an 02 plate, registered around July 2002, while the other was a 52 plate registered a few months later (around Feb 03, I think.) Both were supposed to be the same spec (2.0 Privelege with optional full-screen sat-nav)
Differences were numerous, and some were quite surprising. The following are differences found on the later vehicle when compared with the earlier one.
engine replaced by less powerful 2.0
Airbag disable switch on the end of the dash (no way of disabling the airbag on the older one.)
Renault logo on the iconic dash display is gone, but tyre pressures are shown on certain displays.
Voice synth has disappered
17" wheels have shrunk to 16"
Carminat displays remaining journey distance on main navigation screen.
CD changer is missing (this was later fitted FOC after much arguing with Renault.)
Parcel shelf sun blind is missing (rear window blinds are still present.)
I think that's about the top and bottom of it. There may have been other differences.
The 05 has the reversing sensor disabling switch fitted as standard. Not that I've ever bothered to use it, even with the caravan on the back. I think it's the middle of the three (with ESP disable to the left and cruise/limiter to the right) though I couldn't swear to it.
The voice synth on my old car was a split switch, with two buttons occupying the one position. One was a latching switch that disabled the automatic speech and replaced it with a chime. The other button, a momentary contact, reported any current warnings regardless of the position of the other switch, or said "Welcome, the vehicle computer is now checking systems for you" if no fault was present. (That particular bit seemed a bit Buck Rogers to me, but I rarely bothered pressing the buttons anyway.)