I think there is a difference between an L3 and a P3 guys, keep an eye out. I was told at Basingstoke Nissan that an L3 they only check a whole load of stuff, but on the P3 they replace it. Hence in warrenty you get a P3 as to keep the warrent you have to change it, but in reality it may not be warn and can get away just checking it. I'm sure someone more knowledgable will pipe in with the specigfics.
I just got my P3 done for free at B'stoke Nissan because of poor service when I bought the car. Fair play to the dealership they came through and the service didnt cost anything However, I got some new pads and discs done all round at the same time which they charged me ~4hrs labour for I thought it was all in the service (i.e. gonna be free), but apparently not. Bloke did knock £30 off, but was still expensive. Still he informed me Nissan want £1400 for pads and discs all round and I got uprated ones for £800, so not all bad! Thanks to BigPhil for brilliant service once again, managing to get me pads and discs from different locations within 3 days even though EBC were out of stock!