I have flown this route a number of times. My perception is their are good opportunities to land in the Lea valley area including the reservoirs, but few opportunities south of LCY for a short distance.
I think being realistic whilst their are some green "fields" even at 2400 feet how confident can we be that we could select a suitable field (perhaps at some distance) which on closer examination would be free of people or hazards. If it proves not to be the case other options are likely to be poor.
That said on how many occasions have we found ourselves taking off with few if any options to ensure a safe outcome and for that matter on how many occasions are we below the glide slope on the approach with the result that an engine failure could result in a similiar situation.
It seems to me these factors are all part of the overall risk assessment and it may well be flying the "Lea valley" is pushing the risk to far for some.
On the other hand commercial IFR operation of singles (albeit with turbines) is nearly with us. Now tell me if the aircraft was unlucky enough to have a turbine failure in IMC with a base of say 500 feet whether the pilot(s) would have considered in their overall risk assessment whether or not they could break cloud cover throughout their route and land clear or indeed what chance the controllers would have of vectoring them away from a built up area - and for that matter what about non commercial IFR operations in light singles. How would the CAA react if the outcome was less than ideal and do the "rules" change because we cant see what is below or does the "risk" become any more or any less acceptable?