Ruptly released a video of Assange in prison today. According to the source of the video, the man recording it is a fellow prisoner and the recording is prior to his admittance into Belmarsh Prison’s hospital ward. You can see the video in it’s entirety here.
It shows Assange’s cell somewhat. It appears he sleeps on a mattress with no sheet and there doesn’t appear to be a blanket. However, he does appear to have a decent window for sunlight. Assange remains on the hospital ward as there have been no updates saying differently.
He is kept in his room 23 hours of the day and only released for 1 hour.