I love those old 70s BBC shows, even those ones your nana used to watch. Recently watched all of Upstairs Downstairs, Poldark and currently up to season 5 of The Onedin Line ("Oh you're a hard man, James Onedin!"). Unfortunately I can't get my wife to watch Colditz or WIngs. Bodice ripping she's fine with, stiff-upper-lipped chaps doing battle with the filthy Hun not her cup of tea.
I enjoyed Secret Army. They went on to base 'Allo Allo ' on that programme.