Looking for name of British TV epsiode shown on PBS in the early 1980s - crime/mystery drama - con game

I've been trying to figure out the name of a series/show with a particular episode. Details below and thanks -

• Shown on PBS in the United States 1981, 1982 or 83 (summer of these years)
• British (BBC or ITV produced)
• May have been within the "Mystery!" programme series
• plot fragment: a man and a woman are attempting to run on a con on someone in the English Countryside. They think they have gotten away it, but at the end of the episode as they speed away in a small white car, they lose control and the car crashes into a tree or ditch and the couple/man is killed - the end is very ironic of course and very much in line with twist/comeuppance endings. The last shot even shows the people in car mangled in a TV safe way. For what it is worth, I know at the time the BBC shot video on sets and film on location - this was definitely on film and on location.

I have scoured TV listings with no luck, and even watched entire series (like Thriller) to no avail. This is definitely something made in the UK and has to be some sort of murder mystery/detective type show. Back in the 1980s, the only place to watch UK programming was on PBS.

Also I have ruled out Hammer Horror TV show - this is definitely British made detective/police procedural from the early 1980s.

Thanks for any ideas