Mac keyboard constantly reverting to US from GB

OP wrote " Macbook Pro M3 2024 running Sonoma 14.4.1 " released Feb 8, 2024

First thing would to update to Current Sonoma 14.7

About the security content of macOS Sonoma 14.7

Also, be away this computer does Qualify for an upGrade to macOS 15.0.1 Sequoia with is the current version

How to upgrade to macOS Sequoia

mijbil wrote:

Still doing the same with the latest version of Sequioa. No matter how many times I delete the US keyboard, it reappears and takes over.

That really is strange, don't think I have seen any other reports of input sources reappearing on their own like that. Have you tried a safe boot?

Start up your Mac in safe mode - Apple Support

mijbil wrote:

I've been in to 'settings' and 'Edit input sources', and here there are two keyboards displayed, US and GB. I can delete the US keyboard and save, and this then shows the GB keyboard only in settings for a while, before the US keyboard re-appears and takes over.

First go to system settings > general > language and region and make sure English (UK) is the only item on the list.

Then go to system settings > keyboard > text input > edit > all input sources and use the minus button at the bottom to removed everything except the item named "British".

Let us know if that holds.

mijbil wrote:

. Same with the text input settings too - GB only.

The name of the Apple input source is supposed to be "British". You do see that after the GB, right?

And after some time, you will somehow get two items on the all input sources list, US and British?