I did COTLB too. Any comparison is absolutely fine at the end of the day so long as you follow a logical argument that clearly links.
I talked about the impression of a warrior cult that Tennyson conveys and how he suggests that the only interpretation we should have of war is one of pride, whereas Duffy criticises our lack of concern for growing overseas intervention in militaristic cultures such as "Phonm Penh" - our everlasting support for American military action.
Overall, in War Photographer, war doesn't have as much impact on our lives as it should, but in COTLB then we shouldn't really be distressed by it since it's a noble sacrifice in the eyes of God (Psalm 23:4).