I've used it a few times but that was a number of years ago. It is available but only when wx conditions are extreme from the south west (wind on my last trip was 210/38-45). It normally takes four hours so I am told to prepare 23 for active use, this means moving the parked BA aircraft at the other end, and now from this picture, they would have to move concorde as well.
It takes a very controlled plan to use it in conjuction with 27R departures, departing aircraft cleared for take off after a landing aircraft has passed behind to land on 23. This is due to the thrust of departing aircraft adding to the wind and possible wind shearing effects.