Complex sentence: Mr Rumbold's greatest ambition was to be called to the board of directors at Grace Bros. (he looks up dreamily whenever the word "boardroom" is mentioned), and was usually oblivious to the sex appeal of his attractive secretaries.
Split into simpler sentences: Mr Rumbold's greatest ambition was to become a director of Grace Brothers: he looks up dreamily whenever the word "boardroom" is mentioned. He was usually oblivious to the sex appeal of his attractive secretaries.