There should be a blatant thread that is bumped often: "Where are all the cool single guys in London?" and then inside the first post should be: "This forum is full of cool single guys who live in London and are athletically fit, young and mostly educated. We're here, come take your picking.".
Then you guys should put more interesting profile pics up, and start saying interesting things, and cut out the sexism and racism totally.
It would then all take care of itself as women find us via Google and signup and start riding bikes to attract you.
See above