I think the reason it has not received exposure is that he is with Senators and House of representative officials. They are providing the security and probably have said that prewarning's and drip feeding of the press was not allowed in this case. I would think if anyone had leaked it - the tour would have been pulled and Harry needs this footage and this networking. So I expect them to play along here.
He is with who? It is the organisations themselves that are realising it on their own social media…to get attention they need I warrant but the media appear to have zero interest. Perhaps media in the actual countries are interested.