When Thomas is walking up the hill towards the cemetery in the opening scene, you can see a dozen or more factories in the distance behind him with smoke billowing from their smokestacks. During the entire time Thomas walks up the hill, none of the smoke moves at all, even though they are tilted over by an apparent breeze. Obviously, this is a post-production backdrop put in to look like England in 1919.
When Grace and Inspector Campbell are meeting in a garden a loud roaring engine of a sports car is heard in the background (0:28:50).