Tbh, the way their databases work, if someone entered keywords and reporter's and/or presenter's names and the suspect's name while logging a 'recent' image/video for use in a news bulletin, and then an hour or so later or the following day another producer is searching for that recent multimedia content by searching for his unusual name, there's a possibility that the system threw up older files along with the current content that had been logged with that name, along with other key information, date, time, 'story name' (slug), etc.
Or then again, given his unusual name and how some BBC staffers have longterm careers in the corporation, it's possible the name rang a bell with someone who'd been involved in recording/broadcasting the older stuff, and then they ran a search of archives because they thought there might be something there.
I doubt someone thought 'Let's check the archives just on the off-chance that we might randomly have some footage of him from years ago.'