Whose game enough to call the Cust Service office at Wembley Stadium (Details on thier website) and pretend to be either 1) An A&M employee \2) A rep from a ticket agency or 3) A rep from the touring company, someone like a sound engineer.
Anyway someone calls and pretends they have some credible credentials and asks to speak to the Events Manager or similar. When they get someone on the line they say "I'm calling in regards to the Police concert on July 21s, and I'd like to set up a meeting with blah blah blah" Now if there is going to a be a Police concert then hopefully the staffer at Wembley Stadium will say something to indicate that indeed there is going to be a concert. Maybe something like, "I'll just check my calendar and see if I can arrange for Mr Smith to join us for the meeting" (If you work in an office then you'll know what I mean) At this stage you can hang up and get back here pronto to help us all break out the champagne!
If there have been absolutely no tentative plans made for a Police concert at Wembley then person on the phone would probably say "I'm sorry, you've lost me........ a concert with whom??"
At this stage you hang up, break the bad news to us all here and we can go back to fretting and chewing our fingernails.