While the opening scene says it is supposed to take place in July 1940, all characters are dressed in fall clothing, the trees are changing to fall colors, and the ground is covered in fallen leaves in many scenes. Surely, this was filmed a few months later in the season than July.
In scenes set in 1940, the villagers were given instruction in administering cardio-pulmonary resuscitation. However mouth-to-mouth resuscitation was only introduced in the 1950s and the chest-compression technique was not introduced until the 1960s.
When Pat is trying to lift Bob, she says "I'm not tall enough to get the right amount of leverage" and pronounces "leverage" as "levverage", the American way, rather than "leeverage", the British way. The former pronunciation is uncommon (apart from in business-meeting jargon) in the UK even now, and was very unlikely to have been used by a Cheshire housewife in the early 1940s, before the influx of American soldiers.