It seems the BBC and SRF visited Stockholm to film footage at the same time: The BBC filmed the Multi-Coloured Swap Shop appearance and SRF made the Musik scene interview. ABBA also recorded a brief trailer for their upcoming 22 March 1978 appearance on the programme Karussell on SRF - but this show was never realized.

Therefore it remained as only a "planned" TV appearance, so this trailer-reel was archived and lay waiting to be discovered TV vaults and is now available on the website of the TV channel.

Frida: Do you know that ABBA is on the Karussell Show tonight? See you!
Benny: Hello, I'm Benny from ABBA and we are going to be on the Karussell Show tonight. I hope you're going to like it.
Agnetha: Hello, I'm Agnetha from ABBA. Hope to see tonight you on the Karussell Show.
Björn: Hello Karussell viewers, see you tonight.

Karrussell trailer, 1978;
Karrussell, 1979;
Karrussell, 1979;

Thanks to Mike Dudley, Kaarin Goodburn and Jozsef.
YouTube link c/o SRF Archive