Geri and Christian Horner are in talks for their own docuseries. The Spice Girls singer and the Formula 1 Red Bull Racing boss have been approached about a fly-on-the-wall series documenting their personal lives and they are considering it. A source told the Mirror: “The idea that has been pitched is a really personal documentary, capturing Geri and Christian at home. “Following the recent speculation about their relationship, there would be a huge amount of interest in seeing them together away from the race track and how they interact with their friends and family.” Geri, 51, is said to be o…