Sergio Perez wasn’t solely to blame for his latest poor result at the Sao Paulo Grand Prix on Friday. Perez qualified down in 13th for Saturday’s Sprint. Unlike his competitors, he didn’t have the chance to set a second lap in SQ2. Perez didn’t make it to the line before the chequered flag, so there was clearly an operational error from Red Bull. But externally, this will only add to the growing feeling that his time is up. A rumour ‘erupted’ last week that Brazil could be Perez’s last race with Red Bull. Some would argue there’s little reason to make an early change. The Bulls are already 54 …