The Sun Herald, Sydney, 11-7-71
An article taken from The Daily Telegraph 10th. March 1968
Popping Down to Rome  
Rome stayed cool! At the onset of Hannibal and his elephants,Attila and his Huns . . . Why loose your cool for Zoot Money and his Dantalion,s Chariot, Blossom Toes, The Crazy World of Arthur Brown, Donovan, The Family, The Move (top of Harold Wilson’s pops), The Soft Machine, The Incredible String Band, Traffic, Pink Floyd, Captain Beefheart and his Magic Band, The Byrds, John Handy, The Crome Syrcus with Astarte Ballet, Buffy St. Marie, Julie Driscoll, Fairport Convention, The Pebbles, The Dragonfly, The Robati from Jugoslavia, The Javeri Manipuri Dance group from India, and The Warsaw Skiffle Group from oddly enough Warsaw! And who said poetry is dead anyway ?
Melody Maker: “The pop-flop of ´68″
The festival was announced for the Palazzo delle Sport in Rome, but happened in the Piper Club obviously without the ISB.

Another Festival at which they actually didn't play:

Suomen Turku No 2 1970:

Turku veranstaltet ein großes Pop Festival vom 21. - 23.8.. Die Performer-Liste reicht von der Family, der Incredible String Band, Colosseum und Juicy Lucy aus England, ...

Turussa järjestetään suuret pop-festivaalit 21-23.8. Esiintyjäluettelon nimistä mainittakoon Family, Incredible String Band, Colosseum ja Juicy Lucy Englannista, Made in Sweden, Pugh Rogefeldt och Hjärtans Hundar Ruotsista, Burning Red Ivanhoe Tanskasta, Flamingo Prahasta sekä kotimaisia huippuja.

Excerpt of flyer for  Windsor Festival 26 August 1972. Probably the ISB didn't perform.

Hokey Pokey magazine
A Festival they didn't play
A Festival they didn't play ( O ISB )