The bulbs for the brake, tail, and turn signal are all part of the same socket assembly. Instructions for changing any one of these bulbs is the same. These instructions are for the saloon/sedan model. I do not have any experience with the estate/station wagon.
Start by opening the trap door in trunk behind the tail light in need of attention.
The bulb assembly is clipped into place and can easily be removed by squeezing the two clips together, as marked in the photo, and then pulled out.
There are three bulbs per side; a brake/tail light, a tail light and the turn signal. The bulbs are marked in the photo. The burned out bulb is removed with a light push in, a twist and then pulled out. Instal in reverse.
The assembly is then clicked back into place and the door is closed. Test your lights to make sure everything is in working order.
The bulbs are:
7507A (amber)- Turn signal
7528- Brake light/ Tail light
7528- Tail light