It always surprises me how many singles pass over my house on the Biggin - City - Lea Valley route, usually at weekends when the City CTR is closed (and therefore class G). There's no way that they could land clear in case of engine failure. The whole area counts as congested from the southern fringes of Bromley right up to the northern Lea Valley reservoirs, the CAA have made this clear in AIC's. They should do a little rule enforcement in this area.