Search block routing

I have a new dashboard built using the Layouts, custom template, and which includes the BD system Search Block in the blocks for it's UI. All well and good, but I am doing something special with the other blocks on the layout, in that each of them contains links that open up a colorbox iframe. That works nicely...but what I cannot figure out is how to get the Search Block to open into the colorbox iframe modal. Any clues?

Example link to launch modal colorbox, with a class "colorbox-load":

https://mydomain.nz/heart/volunteers?width=90%25&height=90%25&iframe=true