There may be a multitude of reasons why they haven't - some relatively straight forward and explaiable whereas others, potentially, may be more concerning.Multiple news outlets have run the story so not sure why some in particular havent. Victoria Derbyshire of the BBC has tweeted and Henry Winter of the Times.
The latter is more unlikely. While the police may 'aware' of the allegations, we're unsure if he's been questioned yet let alone arrested.
Although he's been publicly named on social media, perhaps some organisations are waiting for the official line before naming him, if that makes sense.