My reply (just arrived from the Beeb) says:
"So, while other channels were saying the aircraft was probably a Hercules, our defence correspondent was able to say he was getting "strong guidance from a supposedly reliable defence source" that it was not. In saying it could be a Chinook helicopter, we made clear this was what sources were saying rather than an official announcement or established fact. On News 24, for instance, our defence correspondent said: "We don't know yet for certain whether it was a Chinook. The MoD isn't saying. It's an indication we've had that it might have been."
A pretty weak explanation, which does not justify their damaging speculation. 'Not a Hercules" is a very big jump to 'could be a Chinook'.