Goodie,
Good point well made!! No such thing as a "half colonel" of course.
IIRC the pongo etiquette was "no rank in the mess", accordingly all up to and including major were on first name terms, then there was simply "Colonel", whether half or not.
Btw, MM, as per earlier chat of "smart casual" = chinos and shirt, oh dear oh dear, would one go to church thus ? No jacket, no tie? Light tweed suit with brown brogues , unless post polo match when Blazer and/ or those so smart pink cords are de rigeure?