Commander Millington's mustache is against military regulations. Men must either be clean-shaven, or have a full beard and mustache, not just a mustache or just a beard.
The Doctor states that they are in 1943, but the Russian soldiers are equipped with semi-automatic SKS rifles, which were not developed until 1944, and did not go into testing until 1945 in Germany. The SKS was finally adopted by the Russian army in 1949. In 1943, Russian soldiers were commonly equipped with the Mosin-Nagant 1891/30 bolt-action rifle, or possibly its M44 carbine variant, which was being field tested in 1943.
When the Doctor and Ace go to Maidens Point and find the Russian secret orders just as the Doctor asks where they came from the close up of the Doctor you can see a scuba diver near the top left of the picture.