Here's how I went about fixing my leaky brake light. First I disconnected the harness Next up is to remove the two nuts, located in the outer two holes. If you look into the two smaller holes inboard on the holes with the nuts you'll be able to see a plastic snap feature on the brake light. You can just see one of them in this picture To be able to remove the light you need to cut through the existing seal. Ideally some fishing line would be good for this. Get it undo the light & saw back & forth. I used an old store card. This fitted undo the light well & I was able to cut the seal with it. Then using a bit of force I managed to pull the light off. You can see the old seal on the back of the light. I gave the boot lid a wash,t-cut & wax. I also touched up a couple of chips From the edges of the cut outs. Using some white spirit & elbow grease I got all the old seal off the brake light. You can see on the back edge of the light hook features & on the front edge the snap feature. I bought some Unibond Extreme Repair Sealant. Good for exterior water sealing. I then generously applied it to the back of the light. Then re-fitted, applied pressure for a few minutes, cleaned off the squished out sealant. Then wipped the paint down to remove the sealant using Meguiars Quick Detailer. Looks good, just hope it keeps the water out.