The movie is set during World War 2, which ended in 1945, and the bus William and Mrs Beech alighted from wasn't built until 1947.
The steam locomotive carries a smoke box number plate. These weren't used on Great Western Railway locomotives. They weren't fitted until British Railways came into being in 1948
During this programme we sometimes get a view of other houses / cottages in the village. It is a shame that with all the other detail and thought that went into the making of it, no one thought to remove or disguise the UHF television aerials on their rooves ! You would not have seen an aerial of that type on a roof until the mid 1960's when BBC2 came into being.
The opening scene sees Mr Tom and others walk to church past flowering Clematis Montana and a flowering cherry tree which are both in bloom in May. At church they hear of the outbreak of WW2 that took place in September.
When Tom is asking the woman for clothes whilst repairing the roof. The guttering behind him is plastic, definitely not correct for the period.
Near the beginning of the film, Willie is told by his presumptive teacher that he'll be calling her a "Mrs." due to her recent marriage.Female teachers of this time could well still be expected to quit their job (the so-called "Marriage bar") and especially the school being situated in a rural area as the village is.