Biography Film & TV crew member based in Essex but mainly working in London. Occasional writer and "Knobcheese Journo".
Phil,
based in Essex says it all, and whilst I don't know you I'm sure you're not a knob despite your daft questions. If the guy's a military officer and you don't know his rank and it's a formal occasion call him/ her sir/ ma'am. He/She will let you know if that's OK or if a less formal address would be appropriate. If at a relaxed social function introduce yourself and take it from there. Simple really...one does not need a book on etiquette.Watch out for their spouses however.