This is actually easier to do than explain, as a 30 year Telco install tech the mousing of wires and cables in tight spaces is second nature. To get left hand tail light wires and the number plate light wire through successfully you will have to do the mousing with the fencing wire or yellow tongue from the left side of the vehicle. Firstly get a large/long zip tie, make a loop by just starting to do up the tie, now fold it in half and feed it through the hole for the numberplate wire and push it all in so it forms a loop inside the beaver panel. Take off the running light above the bumper and feed your wire or yellow tongue through the hole and down into the beaver cavity, keep feeding until it comes out the other end, Having it go in through the running light hole makes it straighter than trying to do a u bend from inside the quarter and you have more control when pushing it through. As you feed it in you can feel if it hits an obstacle, having it straighter means that you can twist it to avoid snagging, if you use wire, you can bent it like a crank handle and rotate it to clear obstructions. When you can see the end at the drivers side of the beaver panel, pull on the zip tie in the number plate light hole and if you have done it right the mouse should be caught in the loop of the tie, if it isn't pull the wire back and redo the loop and try again. You need the wire to feed through the loop in the zip tie. If it is caught in the zip tie pull it up into the quarter, go to the other end and tape 2 (TWO) lengths of electrical wire to it making sure they are different colours. Now pull the wire through the beaver panel until the two wires are all the way through and the ends are in the quarter. Attach one wire to the loom and one to the number plate light wire, using the zip tie, pull a loop of the wires out the number plate wire hole and cut the zip tie. Pull the wire attached to the number plate wire all the way out and from the left side of the car pull the wire attached to the tail light loom all the way to the left. Your wires should be through to the right places now. I did say it was easier to do than explain!!!