I think the other posters mis-understood the question. This site has a map at the bottom showing the 'Essex Way' which appears to be made up of green lanes.
There may be some "Green Lane"s in Essex, but if there is one in Dagenham then that's not in Essex. It's the sort of name which probably has lots of it everywhere.
The questioner asked 'where can i find green lanes in essex?' Now assuming this was a serious question, I replied in a serious manner. There is a 'Green Lane' without an 's' in Dagenham IN Essex RM8. If it wasn't a serious question, then perhaps it should be banned AB Ed.