It is difficult to think of a comedy series which is so watchable and which may truly be described as "situation comedy" (in a positive sense). A couple, she then a nurse and he a sub-lieutenant posted abroad, parted many years ago when due to a letter lost in the overseas post each thought their romance had ended. They meet again by chance and after an initial stiffness between the two, find that quite unintentionally their relationship blossoms again.
This is not a gooey love story, but a well observed and wonderfully acted comedy romance in which the cast,over time, age well with their characters. There are two great stars in Judy Dench and Geoffrey Palmer. The remainder of the cast (with at least 5 well known faces from time to time appearing) support the thread of this re-gained re-lived romance whilst their characters provide the opportunity for the story lines around which most of the episodes are based.
In the Marmite sense, you will either love it or hate it. It would be a fairly sad world if most people did not fall into the first category.
There is a second boxed set to complete the series (as well as a "Specials" DVD) and these are well worth having to complete the collection.