Surely 'Bridge on the River Kwai' isn't a NAZI war film ?
Battle of the River Plate is a typical Brit flick, Das Boot & Downfall are superb portayals of what war is really like, ( and as with Downfall, try watching Boot in german with subtitles - it's much better ).
Any old b&w film with John Mills - Dunkirk, Ice Cold in Alex, Above Us the Waves, etc.
Battle of Britain / Angels One Five.
The Cruel Sea
Von Ryan's Express
Casablanca ( ? )