First of all, some people see fit to judge a TV series by its age. Okay the TV of yesteryear didn't have fancy production values or pretty faces who couldn't act their way out of a Johnny. However, look past the modest budget and focus on the acting and the writing!
A series like "The Man in Room 17" is a typical example: you have seasoned actors from the theatre in the main roles, being Richard Vernon and Denholm Elliott. They more than pull their weight in this series about Government operations and such like. Yes, this can be a talky programme but it is worth sticking with.