I'd never heard that Anderson had any possible relationship with the BBC until the 1970s. His entire methodology developed within the financial support and risk-taking possible in Lew Grade's internationally-minded ATV/ITC; the BBC couldn't have afforded it. One has only to look at the recently unearthed documentation on The Daleks TV series, proposed by Terry Nation in the mid-1960s and reported on earlier this year by Nothing at the End of the Lane, to see how they were alarmed at the potential costs of a filmed space adventure series.

Blake's 7 wasn't a children's programme, though it probably suffered from the perception that SF was a juvenile form. I think Gareth Thomas has complained about that.