Looking at this it's very cool.
The only thing that confused me was not documenting the repo and commit for the QR-Generator-PHP dependency.
It looks like Terence Eden has a GitHub repo. They work or did work for the UK Government and have interacted, not just forked the repo, so it might be a good source (I'm assuming the original was harder to track?)
https://github.com/edent/QR-Generator-PHP
Would you be open to a PR for this?