Of the original 625-line PAL colour videotapes, all except Episode Four were wiped for reuse. However, a converted 525-line colour NTSC version recorded off-air from an American broadcast was made available to the BBC. This version was abridged and unsuitable for transmission as it was not of broadcast standard (the US recordings were made on a domestic Betamax VCR from a repeat in 1978). In 1992 the colour signal from the NTSC tapes was used as the basis for restoring the colour to the 16mm monochrome telerecordings of episodes one, two, three and five. These versions were subsequently repeated on BBC2 on consecutive Fridays in November/December 1992 (20/11/92 to 18/12/92 at 7.15pm). The ratings were 2.52, 2.96, 2.30, 2.19 and 2.34 million viewers respectively.