Macbook M1 Pro 2021 arrow keys not working (Sonoma 14.1)

My MacBook arrow keys have stopped working, and this is complicated by a couple of other issues...

Whenever I press the enter key, it also enters a '

and pressing the space bar precedes the space with a ]

The down key, for a short time, also entered a [ without sending the arrow key down.

This happened in the middle of playing a game online, there were no spillages, no dirt hitting the MacBook. I've rebooted and shut down and restarted numerous times, I've created an alternative user and had the same issue. I don't get the issue using the Keyboard Viewer keyboard, or an alternative plug in keyboard.

I've also tried the NVRAM -c command in Terminal to try a further resetting of the NVRAM, but it hasn't helped...

I am hoping that I have somehow managed to unlock some strange keyboard shortcut to create this, rather than there be a mechanical issue with my MacBook that will require an expensive repair...

Please help!