How do you change a brakelight on a Fiat Punto?

Under the carpet in the boot of the car there is a tool kit sitting on top of the spare wheel. There is a small cylindrical plastic piece with a female hex fitting in it. On the rear pillar above where the seat belt comes out there is a circular plastic piece that you pop off. Carefully put the hex end of the tool into the hole and inscrew the nut inside. There is another nut about level with the boot sill inside the boot. Remove the cluster and unclip the wiring, remove the back of the cluster with the screwdriver. Change the bulb and reassemble. Easy enough but the nuts can be fiddly.