IMHO I believe most Ppruners viewing this thread (well those with Robbo experience/knowledge) will already have a pretty clear idea of what happened here
No this one doesn't have a clue as yet, if the witness correctly reported smoke, then it may be hot oil smoke from one of two sources, that is why i am intrigued. I see what looks like part of a blade left side of pic.
Does the AAIB publish interim reports within a specified timeframe?