Please try and show restraint from the modern trend of wanting everything immediately.
The AAIB have never, in my observations, delayed or supressed a report. What I do see when they publish a report is one that is clear, unambiguous in what it says and sticks rigidly to the facts, making recommendations as it sees fit.
It is my understanding that all BA RR powered B777s now have modified fuel/oil heat exchangers fitted and so the apparent dangers appear to have been dealt with according to the known facts so far.
What is the problem apart from impatience on your part?