My nephews mother in law has fallen for this twice! The first time she was sending money to a man in need of an operation!
The second was worse, she fell for an American online, moved to America and lived with him. He started by denying her access to her own money - saying she didn't understand the American banking system, when she said she wanted to leave he took away her passport. When he was out she found her passport and rang her daughter who purchased a plane ticket for her online and told her to go to the airport, and once at the airport to immediately go to the departure lounge so he couldn't get to her. He turned up at the airport demanding to see her - she explained the situation to the airport security who stayed with her until she was able to board the plane to return home.
The sad thing is she is still on these dating sites and talking to various men around the world.
Estranged Son and Future Granddaughter
To think that London, or anywhere else for that matter, does not belong to any one demographic