Nothing that caught my eye for this date.
ii) broadcast anniversary
11 July 1964: broadcast of 'Hidden Danger', the third episode of the story we now refer to as The Sensorites, having been postponed for a week because of Wimbledon and cricket. Starts with Susan being uncharacteristically assertive against her grandfather, the Doctor (this is one of her best stories as a character). Team Tardis (apart from Barbara, who is getting a couple of weeks off) then travel to the city of the Sensorites, who are internally divided about talking to them; and as they sit down to eat, Ian collapses to the ground, poisoned. (Cue theme music.)
iii) date specified in story
11 July 1982: was the day of the World Cup final 28 years ago, as it is today. Little did anyone realise that the Eighth Doctor and Charley Pollard were averting invasion of Earth by the Threllips, as revealed in the Big Finish audio special, Living Legend (a successfully humorous short play).