Hi James-from-wales,
Thank you for participating in the Apple Support Communities. We understand you're stuck on a macOS Recovery screen and your keyboard and mouse are unresponsive. We'd like to assist. Are your keyboard and mouse wireless? If so, do you have a wired mouse and keyboard you can try? If not, this article has some steps that may help:
If you can't connect your Magic Keyboard, Magic Mouse, or Magic Trackpad to your Mac
If those steps don't help, you can try booting to macOS Recovery over the Internet by holding down Option-Shift-Command-R during startup. This article explains more:
Use macOS Recovery on an Intel-based Mac - Apple Support
If the keyboard and mouse work in Internet Recovery, we recommend choosing Disk Utility and running First Aid to check the disk for errors. This article has the steps if needed:
Repair a storage device in Disk Utility on Mac - Apple Support
If there are no errors on the disk or it's able to repair them, you'll likely need to reinstall macOS after that.
Take care.