It should be said that the reason the AAIB take so long is they do a VERY thorough job, so the report, when you get it, should be as close as you can get to answering your questions. But there may be things they can't know without having been in that cockpit, bearing in mind light aircraft don't contain voice or flight data recorders.
Reports appear on the AAIB website, or, no doubt, someone will post a link here when it's published.