The situation was a room full of foreigners learning English; the comedy was... a room full of foreigners learning English. The most notable foreigners in the series were Francoise Pascale and her breasts and Evans found them quite a handful. The programme was axed in 1979 (revived for a season in the mid-1980s), Evans dropped out of sight and that was pretty much the last the public knew.
But life out of the limelight went on, and a week ago, Barry Evans went to work as usual. That was the last his friends and neighbours saw of him.
On Monday, police in Leicestershire stopped three people driving Evans' car - a J-reg Montego (not very Hollywood) - and went to his house, a bungalow in the village of Claybrooke Magna, Leicestershire. They found Evans' body that night, arrested the three on suspicion of murder, and ordered a post-mortem.
The actor was back in the spotlight - "Mystery of TV Doc's Murder" plastered across the tabloids, illustrated by that familiar, winsome grin.
"He was quiet, but everyone liked him. I remembered him from Mind Your Language and was gobsmacked when I saw him sitting in one of our cabs,'' Susan Middleton, who works at Crest Taxis, was quoted as saying. "At first, people knew him as Barry the actor, but over the years, he became Barry the taxi driver."
He had played that role in his last film, The Adventures of a Taxi-Driver, a sub-Carry On tits 'n' titters flick circa 1975, and a comedown from his movie debut, Here We Go Round the Mulberry Bush, an "adolescent romp" that became a cult hit. He starred in both with Judy Geeson, with whom he is said to have had a long affair. They never married.
Despite the post-mortem, police do not yet know how Evans died. His body was found, clothed, in his sitting-room, and there were no obvious signs of a break-in. Police have released on bail the teenage girl and two men who were in the Montego and are waiting for the results of tests on Evans' body.
Locally, everyone knew about Evans' TV work, but, as neighbours said: "He was modest and never really talked about it."
Evans had not given up hope of a come-back - "What I want is a long run in EastEnders,'' he said last year. He had discussed the options with his agent, Malcolm Knight. "Barry was still on the books - he had decided to stay out of the business for a little while, basically because he was stereotyped. We were beginning to talk about getting his career back on track."
Starring in a Seventies sitcom is apparently the televisual equivalent of sailing the Bermuda Triangle.
Richard O'Sullivan was Man About the House with Paula Wilcox and Sally Thomsett, the Caroline Quentin and Lesley Ash of the Seventies. Neil Morrissey and Martin Clunes should take note - Richard was so successful that he was given his own show, Robin's Nest. But in 1994, the People reported that Richard had "spoken from a clinic of his decline to being a hard- drinking depressive".
Paula Wilcox still works, in Life After Birth on Channel 4, and in children's television, but Sally Thomsett's claim to fame has been a spread in Hello! to celebrate giving birth at the age of 46. This might not be unrelated to the fact that Wilcox played Chrissy, the sensible one, and that Thomsett played Jo, the dizzy blonde. As Tessa Wyatt, O'Sullivan's subsequent blonde, in Robin's Nest, put it: "You pay the penalty of becoming identified with a particular character so that people find it difficult to see you in any other light."
Thomsett, however, was not averse to playing the same role over and over in life, if not on screen. "The Jo image has been very useful," she said. "I've been treated as a bimbo for years - and, I must say, it's rather pleasant. I've never carried my own suitcase."
The type-casting seems to have been particularly severe in the Seventies sitcom scene, perhaps because so many of the comedies were based on such old-fashioned caricatures - all men gagging for it, all women fighting them off, all foreigners stupid or strange, all homosexuals screaming queens, all doctors male and all nurses female.
What hope was there for Ian Lavender (Private Pike) after Dad's Army, or for Melvyn Hayes (Gloria) after It Aint Half Hot Mum? The latter appeared (in the Daily Mail) under the headline: "After six kids, maybe they won't think I'm gay".
Then there were fewer channels and fewer hours of airtime but more money to lavish on long-running home-made serials. The companies milked their comic actors for all they were worth, placing them in show after show until the public finally cracked and turned off.
And if the actor is not pulling in the punters he is out: Dennis Sellinger, a talent agent who started in the business 61 years ago, said: "People do become unfashionable - it's part of the business we're in. Someone like Barry, who was very successful and then runs out of steam, is not of value. It's nothing to do with talent."
Barry Evans was no Simon Dee, fallen from grace and riches to the gutter. Evans sank gently into decline, it seems, moving to the bungalow in Claybrooke Magna four years and working first for Crest Taxis before setting up on his own. His co-star, Francoise Pascal, had a bumpier ride. The parties went on but the parts dried up. She moved to the United States, discovered cocaine, beat her addiction and shopped her fellow celeb users to the News of the World.
Ms Pascal too is still on the books at Mr Knight's agency, but has had no acting work for years. "Even Celebrity Squares don't call me anymore," she told the Mail. "And I used to be queen of those game-shows."
Mr Sellinger is philosophical. "TV can be a monster. While it can make people big it can also kill them," he said. And once they have sunk into obscurity, sad to say, they normally hit the headlines only when they die. There is the odd exception, though.
When a character in Dawn French's sitcom The Vicar of Dibley said: "There hasn't been a bus through the village since Hughie Green died," the entertainer re-surfaced, demanding an apology from the BBC. "I would be grateful if you would inform people that I am very much alive," he said crossly.