Thatcher has already served 2 games of that ban so will be out for another 6 games. Since City fined him 6 weeks' wages, the FA chose not to impose a financial penalty.
A City spokesman said: "We note the findings of the disciplinary committee and are pleased the FA have taken our own disciplinary action into account."
Thatcher's barrister, Mr. Rupert Bowers said: "Mr. Thatcher deeply regrets the incident. He accepted the punishment from his club and that penalty has been increased by the FA. Mr. Thatcher similarly accepts the FA's decision without question. He again expresses his apologies to all concerned; he now wishes to serve his suspension, put the incident behind him and continue with his career."
This column is now coming from Australia so I missed the incident live but have since seen it on the web.
A football column in one of the leading newspapers out here mentioned it and named City supporters 'Fans of the Week' for booing Mendes when he was receiving treatment.
If this is true I'm very disappointed as although it must have been difficult to tell the seriousness of his injury, it was pretty obvious that it was a shocking challenge.
By all accounts, not Thatcher's or City supporters' finest hour.