In the State nightclub, Theresa takes a cigarette from her packet and goes over to the Russian soldiers for "a light". However, when she returns there's is no cigarette in either hand, either lit or unlit.
Elaine says the British embassy did nothing to help her. It is highly unlikely that that she as a British citizen in Britain would have contacted any British embassy, all of which would, by definition, be in other countries. She would have contacted the Foreign Office, which is the authority dealing with foreign affairs and international matters in Britain. The casual viewer might easily confuse the two, but Elaine, who has recently dealt with them, would not make this mistake.
As Piotr and Elaine say a final goodbye to each other, both on either side of a high fence, Piotr walks towards the ship and, taking of his sailor's cap, throws it Frisbee fashion over the fence towards Elaine. However, when Elaine stoops to pick it up, it's lying close to the fence on her side. If he'd thrown it so hard as to clear the top of the fence, there's no way it would then fall to earth right next to the other side of the fence in this way.
Piotr (Peter) is seen wearing jeans that clearly feature a Levi label. Levi jeans would never have been available in the former USSR at that time.