I'm sorry to read so many posts using the words engine icing and anti-ice in such an unsupportable matter regarding BA038.
Not for many years have these large fan engines used piped hot air to warm up the blades or vanes to keep ice off them. In the air they depend on the compression cycle temperature rise, centrifugal force and air air-velocity loads to shed accreted ice at low enough mass levels to not damage the engine internal parts or affect the engine surge stability.
Whilst tis true that the culprit ice does melt, its evidence on the engine that it leaves behind is unmistakeable to an investigator.
So to me the credibility of the engine teardown examination as well as the memory readouts pretty much eliminates this area still in consideration.