As reliable sources clearly acknowledges, reliability isn't binary: "The reliability of a source depends on context. Each source must be carefully weighed to judge whether it is reliable for the statement being made…" The question is whether they're reliable for what they set out to prove. Flannelette Murmurings would be useless as a source if it was for the idea that Potts is a more important violin player than Warren Ellis or Nigel Kennedy, say, but is a perfectly decent source for the proof of a simple, incontrovertible fact, namely that Potts plays in a band called Cuba is Japan. The idea the author made up the band, and therefore the interview, is exceedingly unlikely. ¶ The other source should obviously have been removed regardless of it's reliability, since it seemed to be primarily about a charity cooking event and didn't match the point it was supposed to illustrate.