Pete,
It looks like you are missing a tab in the bucket. Here is a pic of my fender.
You need to make a tab out of aluminum and rivet to your bucket at the top, and then drill a hole in the fender at the bottom to pass a bolt through to secure the headlight.
You can take better pictures when you come and pick up the 18x10 ... I'll pull my headight apart ... its only one bolt.
Sandeep