Both of those connecters on the towing loom are green and brown.
I'm guessing the existing lighting plug was meant to connect to male socket on the towing loom and then the female goes into the light.
So If my thinking is correct, I need the cut all of the plugs off and connect the existing lighting loom to the plug on the left and then replace the plug on the right with the plug from the lighting loom.
I hope that makes sense, it's been a very long day.
And thanks for everyone's help so far, it's much appreciated.