This bracket screws onto the back of the High-Bright unit using the existing 4 screws.
Available in 7 colours
It has an hexagonal hole in the base which accepts a half-height 1/4”UNC nut to give you the option to mount the unit from the bottom.
Also provides a good flat surface for using velcro should you wish to fix the High-Bright in that way.
The hexagonal hole will also accept a 1/4”UNC bolt, should you want to have a male thread on the base.
Fitting this bracket still allows you to use the Gizmo antenna protector.
In the UK, I have found Westfield Fasteners a good reliable source for imperial nuts and bolts and the links above are to their site.