The most common place for the rattles and squeaks is from the catch. Some dealers have been known to smear the catch with grease - don't do this (it doesn't work very well and the grease ends up everywhere :x: )
The easiest cure if this is the case is to wrap a couple of turns of PVC insulation tape round the 'D' part of the catch. this makes the catch a bit tighter so it does't move.
If the seat itself is not tight enough, there are three studs under the rear edge of the bottom part of the seat (one near each end and one about in the middle) and a furthur one between the two parts of the seat back. This one can be seen easily from in the boot. :mrgreen: