1. 'I've been happy for the whole of the holidays' -- SOUNDS FINE TO ME. SOME ENGLISHES USE THE SINGULAR, SO THAT YOU COULD WRITE 'FOR THE WHOLE HOLIDAY'.
2. 'They were those which treat of the haunts of sea-fowl' -- 'SEAFOWL', LIKE 'FISH', 'DEER', 'GROUSE' AND OTHERS HAVE THE SAME FORM FOR SINGULAR AND PLURAL.
3. 'of the coast of Norway' THE COUNTRY HAS ONE LONG C