It's...something of an odd story, but given that you're a member of the magical community, you may be more likely to believe it than someone who isn't.
My siblings and I are indeed from London - Finchley, to be exact - and we were raised there. I was born in 1928. A number of years ago, when we were all still children, we were forced to leave our home and travel to the country. While there, we entered what turned out to be a gateway to another world, called Narnia. The land was being ruled by a cruel queen called the White Witch whose name was Jadis. We helped the people to overthrow and banish her, and ended up fulfilling a prophecy in the process, which led to the four of us being crowned the country's rulers. Time passed much differently there than it did at home, and we ruled for fifteen years before we ended up leaving. The next time we went to Narnia, more than a thousand years had passed in the meantime. [...] But one of the things we were always told was, "Once a king or queen of Narnia, always a king or queen of Narnia". I suppose I would be considered a ruler in exile, given that I will never see that place again.