Originally, the honest answer would have been Heaven. Because that was where he had started, many long ages ago. That, however, wouldn't have been the slightest bit believable to this young thing. The second truest answer would have been Hell, but for as true as that was as well, it would have scared her away.
The easiest answer, though not altogether true, was to say what he would inevitably tell her, "London." There were no words about where he grew up, because he never really grew up. There wasn't any growing, there was his creation in Heaven and it went on from there. Then a string of bad decisions later and he found himself in Hell.
But there was London. It was where he had called home, over Hell -because no one who had been to Hell would call Hell home in their right mind. It was where, as they say, he kicked off his shoes and relaxed.
He hadn't truly relaxed since he had gotten to this City, even though it was as good as he was going to get when it came to 'home.' At least he still had his plants.
"Sometimes," he said quietly, "I long for London again." He noticed her sudden ocular attention on the sign of the Park and changed his step to go in that direction.