Tail Light Replacement
This is an oddly common job on the V8 Vantage (and DB9), and people do it for a few reasons. Aside from replacement due to an accident, people also put in new tail lights to replace ones that have built up condensation within them, and also to change from red tail lights to clear ones (and vice-versa). This job is actually pretty easy, but requires some finesse during reassembly.
DISCLAIMER: As always, follow all safety protocols. Don't undertake this task if you aren't comfortable with it and fully understand it. You are ultimately responsible for anything you do. Neither Redpants, LLC or myself is responsible or liable for anything that may occur.
Ratchet for the above socket
Small flat-head screwdriver
About half an hour
DIY Under Construction!
Open the trunk of the car. Make sure the trunk struts are capable of holding the hatch open. If they can't you'll need to replace them.
Remove the five large black caps inside the trunk, directly behind the tail lights. Just twist them loose and they'll spin free. There are three on one side, and two on the other.
Pull back the carpet from behind one of the tail lights to fully expose the nuts and washers holding the tail lights in place. Use the 19mm socket and ratchet to remove the nuts and set the nuts and washers aside. There are thin rubber gaskets behind the large flat washers. These are prone to breaking, so be as careful as you can with them, but don't be surprised if they tear.
Be very careful during this step! You don't want to scratch your paint while maneuvering the tail light.
Pull the tail light away from the car until the wiring prevents you from going further, then rotate the outer corner even more to the rear to expose the wiring connector on the backside of the tail light. Use the small flat-head screwdriver to remove pull the red lock tab outward. When the red tab is fully to the side (it does not come out completely), the connector can be pulled from the tail light.
Plug in the wiring connector for your new tail light, snap the red lock tab back in place, and slide the tail light into position on the car.
Put the thin rubber gaskets, washers, and nuts onto the back of the tail light, but don't tighten the nuts yet. Look at how this tail light compares to the one on the other side. There's a small amount of movement to them, so hold the new tail light in place to match the other side while tightening the nuts. Step back and look at how the tail lights are sitting and adjust accordingly.
Repeat Steps 3 through 6 for the second tail light. Once done, check the brake lights to ensure they're working properly.
Put the carpet back in place behind the tail lights, and push the top edges of the carpets back into the rubber trunk seal. Then reinstall the large black caps.