Matthews is calling Regan from a phone box to brief him about the observations he was asked to do, at the same time, he mentions that Mrs Budd has posted a bulky package with some uncertainty and Regan asks Matthews to get it by using his initiative (meaning call the bomb squad), at that moment in time, it is raining and the ground is wet and when the bomb squad arrive in the next scene, it is sunny and the ground is dry.
When Lyon is playing chess with his lawyer they have the board the wrong way around. This is obvious without seeing the board as Lyon's king is on his right being mated, it should be on his left.
When Lyon is playing chess with his lawyer he loses to four's mate, not fool's mate. Fool's mate is a two move checkmate, and the lawyer states , four easy moves.