I did mine a few months ago mate. The previous owner had put a black one on, but it wasn't my cup of tea and I bought a replacement in standard silver.
I'm sure someone had said that you could get it off without removing the front bumper with the aid of a stubby phillips screwdriver and a double-jointed tendency
I'm not sure if it was my big shovel hands, a lack of patience, or the fact that the screws were pretty tight, but I couldn't get them (4 or 6 screws) to move.
I bit the bullet and removed the front bumper. It wasn't actually that bad and from memory involved undoing bolts in the wheelarches, attached to the undertray and at the top of the bumper. If you look it should be fairly obvious. The only other thing that I remember was that I had to pull the bumper out from where it clipped to the front wings in order to slide it forward. This was scary cos' it felt like the (flimsy) bumper was going to snap...but it didn't
After that it was a case of laying the bumper on a rug on the ground, unscrewing the screws behind the grille and swapping it over. It's the kind of thing that you do slowly first time, but you could do it a second time so much quicker!
Hope this helps. It's based on my (notoriously unreliable) memory, but should be pretty much accurate!