iTunes has a sale on a number of 4K war films. You will need an Apple TV 4K (or the latest model Samsung TVs) to watch these in 4K.
You can also combine with the 15% off iTunes gift card deals at Officeworks (https://www.ozbargain.com.au/node/450005) and Woolworths (https://www.ozbargain.com.au/node/449553)
Saving Private Ryan 4K $4.99
Braveheart 4K $4.99
Dunkirk 4K $4.99
Schindler's List 4K $4.99
Lawrence of Arabia 4K $4.99
The Patriot 4K $4.99
Glory 4K $4.99
Fury 4K $4.99
A Few Good Men 4K $4.99
American Sniper 4K $4.99
UPDATE:
Two more 4K films added:
The Bridge on the River Kwai 4K $4.99
The Dam Busters 4K $4.99
The Dam Busters ?