According to the Svensk mediedatabas here, the Hootenanny Singers appeared on this programme.  They did their one and only performance of the summer in Västervik at the annual Visfestivalen.

In its first two years, the Visfestivalen was organized by Mageliso Club, a group of high school students in Västervik. In 1968 they were succeeded by Hansi Schwarz, then a member of The Hootenanny Singers, and Lars "Frozen" Frosterud. The latter remained an organizer until 1977, after which Hansi Schwarz was the sole organizer (from 1978 to the year before his death in 2013). 

The Rapport item was a report from the festival and the Hootenanny Singers performance was seen very briefly.

Rapport (Björn), 1971; 
Rapport (Frida), 1974;
Rapport, 1976; 
Rapport, 1977;
Rapport, 1978;
Rapport, 1979;
Rapport (Agnetha & Frida), 1981;
Rapport (Björn), 1982; 
Rapport (Agnetha), 1982;
Rapport (Benny & Björn), 1988; 
Rapport (Benny, Björn & Agnetha), 1995;
Rapport (Benny), 2004;
Rapport (Björn), 2007; 

Rapport. Inslag 1-3
Stockholm : SR, TV2, 1971-07-14
Namn
Personer Vreeswijk, Cornelis, 1937-1987 (medverkande)
Brandelius, Harry, 1910-1994 (medverkande)
Grupp/institution Hootenanny Singers (medverkande)
Utgivning
År/datum 1971-07-14
Kanal SVT2
Utgivning Stockholm : SR, TV2
Utgivningsland Sverige
Anmärkningar
Speltid 11 min.
Originalformat
Originalets nummer K 31.112 ; L 31.113
Arkiv
Exemplar
MPEG-1 XA_TF09-0015

Thanks to Jozsef and Carl Magnus Palm.