I haven't seen any clear activity on the London sites since the early days of the system, with some techs doing some 'test 1-2-3's'. Beyond that I've seen the same thing... had the odd talkgroup pop up here and there but never any audio. Holding on the talkgroup for a bit usually confirms that it is indeed encrypted. I was going to run UT on the sites for a while just to log the groups.... but didn't bother since it says not to submit unidentified talkgroups to the database.