There's also an episode where they get back the lead's (Marston's) love interest from East Germany. Without providing any spoiler's, the ending of that episode

There's also an episode where they get back the lead's (Marston's) love interest from East Germany. Without providing any spoiler's, the ending of that episode left younger me in shock for days. Still one of the most powerful (fiction) TV moments I've ever seen. I think it was "Special Relationship" season ending in Series 1. But don't watch just that one. Watch them all.