Foyle's War (Greenlit ITV crime drama, (2002-))

Episode 2:4: The Funk Hole
Set in wartime Hastings, 1940: includes an appearance by Mervyns Coaches 1949 Bedford OB/Duple HOD75 through the opening credits (thanks Stephen Osman):

Episode 3.3: They Fought in the Fields
John Hewitt notes a green/cream (postwar) Bedford OB/Duple Vista setting down a stranger in a village:
Tim Wootton advises this is his LTA750 (originally Western National 1411), and has kindly provided photographs from filming, one posing with LTA750, the other an interior shot with some of the extras:
Episode 5.1: Bleak Midwinter
Again features Mervyns Coaches HOD75, a 1949 Bedford OB/Duple:
Episode 6.1: Plan of Attack
Features Dews Coaches CUT465, a 1944 Bedford OWB rebodied in 1952 by Duple. So the body is an anachronism, the chassis not!
Episode 6.2: Broken Souls
Allan Haynes notes the appearance of superb 1939 Harrington-bodied Leyland Cheetah EYA923:
Episode 6.3: All Clear
A distant view of what appears to be Bedford OB LTA750:
Episode 7.1: The Russian House
Features Cobham Bus Museum's STL441 (AXM593), a 1934 AEC Regent. It appears three times as Foyle drives Sam Stewart through London:
Later it appears to be stalking Sam Stewart during a long sequence where she walks through London's streets, appearing four times! It's a long walk - dusk apparently falls twice.