This is the repo containing code and (most of) the data for the analysis contained within this piece: https://medium.com/@fintansmith209/why-is-the-uks-prison-system-in-such-disarray-bbaf41ad2833
To create the aggregated weekly populatio bulletins I had to scrape several hundred files from the MoJ website, and unfortunately I'm unable to upload these to GitHub via the web UI.
However, you can see what the product of the cleaning process was in complete_xlsx.xlsx - which is within this repo. You can also see the different formats of these files on the MoJ website, here: https://www.gov.uk/government/collections/prison-population-statistics