I watched this on ITV 3 today. I must have seen it before but I don't really remember it, except it is largely made up of scenes from episodes in the TV series stretched out into a film so much of it is very familiar anyway. Like all these transfers from TV in 1970s it has its good points and bad but on the whole I enjoyed it. There are some lines that make you cringe these days inevitably and some bits that are still very funny. Richard Beckinsale had died by the time they made this so Christopher Strauli plays John, an art student, to fill that character space. He does a good job I think although Richard Beckinsale was great in the original role. Anyway John is pursuing one Sandra, without very much luck. Glynn plays her irate father who has a habit of turning up at inopportune moments, in one case with a dog and ends up falling into a river. It is not a big part but he certainly has an entirely believable presence on screen.
Leonard Rossiter's characterization of Rigsby is always brilliant. I noticed at one point he pours out a drink for himself and Miss Jones from a bottle of Cinzano, presumably a sly reference to his adverts with Joan Collins.