Hi Verso,
It's good to catch up with you again
53A. Protection = Defence
'of' french = de (french word for 'of')
border structure = fence
50D. Calm = Serene
prophet = seer
strange prophet = sere (letters of 'seer' rearranged)
points = compass points
Includes two points = North and East
sereNE
6D. Animal park = Zoo
last letter = Z
Duck= 0 (zero) (Cricket term 'Out for a duck'- a batsman given out , having scored no runs)
ducks = OO
ducks after last letter = ZOO
Hope this helps. Post again if you get stuck.
Good luck in the competition Verso!
Regards, Butterfly