It was posted on the WWIIOL Hanger forum ages ago. I lost that one but i did a search for it on Google and found it on a site that had various audio clips from 1940's.
I put it on my webspace for safe keeping, as well as my local hard disk.
The site i got it from labelled it as a 1943 recording of a Lancaster over Berlin.
btw.....
BBC reporters flew with Lancasters and made recordings of the crew.
Perhaps this is one of these recordings.
Here is a guy talking about it
BBC war reporters The famous reporter Richard Dimbleby also flew 20 missions with the RAF one of them was this one on 17/18 January 1943
"An observer of this raid was Richard Dimbleby, the BBC broadcaster, who flew in a 106 Squadron Lancaster piloted by Wing Commander Guy Gibson."
RAF Website. BBC reporter halfway down I can't find that recording but i did find another one of him observing a Spitfire strike from the air on D-Day
D Day website