Grantchester is a well-written serial with engaging characters and relationships animated by high-quality acting. Viewers with an eye for detail and historical accuracy may find it frustrating, though: for example, suicide victims could not be buried in consecrated ground in 1954, and Leonard would not have been able to be at all open about his sexuality in society at large, let alone in the church.
None of these things need spoil the enjoyment of the drama overall, and a mild suspension of disbelief reveals sensitive treatment of complex questions which, I sense, were simply not talked about at the time. All of this is played out against the gentle background of the Cambridgeshire countryside and the cobbles and colleges of the University, so it always looks pretty, whatever the plot.