These mimed performances have been credited to "Popshop", a Belgian TV series recorded at Pop Deux studios in Brussels. The date here is speculative and the precise taping/broadcast dates are not yet known. 'Popshop" shows were later rebroadcast as part of the British "Rock of the 70's' series.
"In September 1970 Yes were invited by the Belgian National Television to make a TV-special featuring a selection of songs from Time And A Word. The band would mime their music on different beautiful locations in Belgium. Steve Howe, who had just joined the band, had to fake the guitar parts played by Peter Banks. This special was broadcasted on TV just before their concert at the Huy Festival in Belgium on the 5th of September" -- from Henri Strik's review of the DVD, in the online Dutch "Background Magazine" (see URL).