ins Creed question?

I am riding to Arsurf to inate Robert de Sable, but I stopped to collect all of the flags and templars before doing so using online map guides. I have collected all of the flags from everywhere, but i am missing one templar that i may have skipped by accident, even while using the maps. My question is: what should I do? If at all possible, I like to not have to go back to every city, one at a time, to find every possible place and make a checklist. Where should I look? Or, should I just beat the game, start over, and use the guide to kill each templar in numerical order instead of killing some here and there throughout the game before even beginning the search. Help me please!