Try 'Foyle's War'
Its set during the second world War, Foyle is a detective, good series, I like the character, has a quiet doggedness about him.
Also, if you want something set in more recent times, try, 'Inspector Morse' & 'Lewis' also 'Cracker' (awesome series, Robbie Coltrane - you might know him as Haggard from the Potter movies!) -and maybe 'Wycliffe' - (can't rate that one so much , as I haven't seen so many)
Definitely try Foyle's war though, I have a feeling you may like.