OK, by "from London" I meant as a followup from the previous question, i.e. "Individual Olympic medals from Beijing (2008)? From London (2012)?"
I assume therefore it's Rebecca Romero, who I thought it might have been because of her pretty unique feat, until you said "yes" to from London, as she didn't compete in 2012. Since there's only three British women to have won an Individual gold in Beijing on the track, you've already confirmed it's not Pendleton, which leaves Houvenaghel and Romero, one of whom is from London.