All good questions that I'm surprised more people are not asking, but BBC bashing is a very popular British past time and other UK media organisations benefit from it greatly!
It is weird that the Sun hasn't named the person in question and it suggests that maybe they haven't seen all the evidence and are worried they may not correct. The other possibility is that they are playing the game purely for cash and sales and are building up a frenzy before they finally do their big reveal having maximised clicks and sales, though I would guess it is the first possibility.
For other news organisations it makes perfect sense not to name as all their details are effectively coming from the The Sun in the first place.
It is surprising that the everyone is prepared to take the Sun at face value given their reputation. And I do not believe the BBC given their history would purposefully protect someone they knew had broken the law, it's the most self defeating act you could imagine. I would hazard a guess that they obviously knew something was wrong and have quietly been investigating and have been blindsided by the Sun's front pages.
I suspect we know far from the full story here.