In the perimeter are the six items not given by the clues - there's a comprehensive wiki entry that shows the full list and everything else you need to finish the puzzle.
I think you're looking for the other group headings rather than the entries for just the one spelled out in the circled cells, hankir (there's many more than 12 of them).
Thanks ProfessorM.
I guessed all the answers around the perimeter. Though I have not yet figured out which group they belong to.
I have I,B,E,Y in four corners.
I can change 4 letters in one direction to get a Holiday in that country.
I will now have to figure out what 4 letters to highlight.