I did a temporary fix for mine when I got rear ended in my SR which was so effective it could have been permanent.
I had some heavy duty adhesive plastic film. Actually designed for protecting the top of the rear bumper from scratches. It never got used for the original purpose.
I cut a piece about an inch all around bigger than the hole the number plate lights fitted into. In my case I had access from another angle once I put it in place to bring the lights back down and stick them to the film, thus holding them in place.
I still have some if you think this could work for you. I could post you a piece if you gave me the area you need.