There have been times when the BBC has made something of a hash of televising the classics (King Lear was one example), but rarely have they made such as hash as their version of Northanger Abbey, made in 1987 with Peter Firth and Katharine Schlesinger. Robert Hardy and Googie Withers also appear; Withers is fine in a truncated role as Mrs Allen, but Hardy seems totally ill-at-ease, as though he's either not sure what the role is all about (he plays General Tilney) or he's found that the production wasn't living up to his expectations and he is trying in part to sink it. That's probably unkind; most actors do their best not to assist productions to sink, and anyway this one is sinking from the opening scenes without any further help from the actors.
The script adds and subtracts, seldom adding to any advantage and often subtracting to great disadvantage. It loses the point that Catherine Morland (Schlesinger, all googly-eyed as though her eyelids were permanently stuck wide-open) is so enamoured of the Gothic romance novels of the period that she views everything about her as though it was coloured in the same way. Instead, we have crazy inserts of the Gothic stuff she sees as though it was some kind of reality, and these are never really explained. She never actually grows from being obsessed with the romances to seeing real life.
Firth isn't too bad as Henry Tilney, one of Jane Austen's regular older and wiser men whose role it is to bring a young woman into a place where she's not so self-obsessed and flighty. He's charming, though not particularly handsome. Why Catherine would fall in love with him at first sight is a bit difficult to understand (or he with her, if it comes to that). His worst moment however is when he's required to sing some Italian duet with a woman who's role in the film is never clarified. Firth isn't dubbed by someone who can sing; instead we have to endure a couple of minutes of him singing with a voice that has little vocal quality whatsoever. Its main blessing is that it's in tune.
The Thorpe brother and sister are presented as plain awful: Jonathan Coy plays John Thorpe as one of those brusque characters out to win a bride to fund his ongoing living. He at least knows the style of the thing. Cassie Stuart, however, has no idea of the style or period. Her speech has no quality to it, she's forever giggling and gushing, and her only moment of truth is when she's dumped by Catherine's brother because she's been giggling and gushing at Henry's brother. On top of this she's dressed like someone who has no sense about her clothing at all. Not that she's alone in this; this TV play must be one of the worst dressed on record for both men and women.
And then there's the music: for a start there's too much of it, blowing its way into scenes where it isn't needed, and at other times so anachronistic that it breaks any mood it's trying to convey. The user reviews on IMDb.com, which seldom agree with each other, here universally decry the music, especially the use of a saxophone and some wailing woman that occurs on more than one occasion. The reviewers in this instance dislike the play almost entirely, in fact, which again must be unusual both for IMDb and for the BBC.
For some reason this particular film doesn't show up in IMDb's search engine. You can find it via Google, where the additional tag, 'Screen Two' is added; this appears to have been some series that the BBC produced around that time that were intended both for TV broadcast and theatrical release.