For some reason I thought the XR had front fairing mounted mirrors instead of bar mounted. That clamp isn't going to work on bar mounted mirrors because the mirrors aren't far enough forward mounted.
You do not have to surrender footage to the police. Whether they can take it from you without you noticing... different story. Also, if they have you for something else serious, in certain circumstances, they can (when they can search you).
There's an old thread partially on the topic.
can police seize your video helmet cam??