There’s a guy on the Historic forum – von Perthes – who appears to have a record of absolutely every wartime crash. Whether his records reach post-war or not, I don’t know, but I’ll send him a Private Message on your behalf, as you are a newcomer, and alert him to your thread.
Do you know what type of aircraft it was?
I’ll also send a message to YakRider as he has been known to venture near Southend, he may know the addresses of the local newspapers.
Good luck and welcome to the forum.
It was a Proctor 111. regards Stenjoe