When Terence Philpot chats with the Bishop on the train, the view out of the window shows them to be passing through countryside and traveling at a high speed, even though in the previous shot the train was only just pulling out of the station.
When Sid James pours water over him from the fire buckets and pretends to have attempted to drown himself in the canals, Joan Sims helps him into the flat but his clothes appear bone-dry in the next shot.
When Terence Philpot gets out of his car to visit Jenny Grubb, he looks in the back of the Mini and sees the couple, in the background you can see the shadow of the boom mic.