When someone "helpfully" seeks advice for a friend, it invariably ends up as some form of Chinese Whispers. Unfortunately, the Admins won't let me string those involved up from the nearest lamp post.
If he's only been charged with the s. 172 offence, there's no option of doing a deal to plead guilty to an offence he hasn't been charged with (although it was apparently common practice for the instant when Harriet Harman was allowed to do it - but never before or since).
I note that a partial statement setting out a version of events has been included in the images of the PR, which will be before the court. The version of events in that statement appears to contradict the OP's statement that the RK was invited to provide "correct" driver details.
However. I would be wary of advising the OP's friend to challenge the statement, or give evidence at all (or attend court), as currently there is merely a very strong suggestion that he was perverting the course of justice, but unless he chooses to give evidence there is no opportunity for the court to put the question to him under oath.