Possible Clues:

• Grandma has struck arrogant pose outside — someone to ignore
• Character shortly to discover new head has left Granta as outcast
• One not diplomatically acceptable to a foreign government
• One banned, diplomatically, from Goa? So partner Ann broadcast
• Unacceptable type of black sheep in Rome perhaps
• Undesirable and mostly arrogant, opens up
• ... diplomat not wanted as Republican in Pentagon, NASA or otherwise
• Great rap moves involving boy, soon an outcast
• Colonel Sanders at a hen party?