In Studio Prop: Menu Edit > Fund Advanced, Sear for Add-on widgets and select your widget
Ok, that was a bit embarassing. I’ve just found in the ctrl+f search there is an option for “Page widget name, class and style properties” which solved it.
Leaving the answer up in case anyone else struggles with it.
What about widgets that are in the toolbox out of the box i.e. not add-on widgets? For example i’d like to find all usages of the File manager widget and the find options dont seem to do that?