Complex sentence: This related most specifically to a meeting in July 2009, which became known colloquially as "the vault", in which Connolly allegedly openly discussed the potential benefits to the club of tanking.
Split into simpler sentences: This related most specifically to a meeting in July 2009. This occasion became known colloquially as "the vault" meeting, in which Connolly allegedly openly discussed the potential benefits to the club of tanking.