I had the same problem with another language and almost tore all of my hair out trying many different suggested solutions until I finally found the solution that worked for me.
The problem (for me) was that the user interface design of the Windows 10 PC Settings is really bad in this case.
First, in the PC Settings Region and Language, click "English (United States)", even though you don't want to remove the "English (United States)" keyboard layout. (This is where the bad interface design is – why would you look there for "United Kingdom" if it says "United States"?)
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/JlTl9.png)
Then click Options. I can only send you a Danish screenshot to illustrate, as my Windows is in Danish, but it can likely be understood anyway:
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/0r1GN.png)
Now you will see that there is in fact a United Kingdom layout there under "Keyboards" (again, my screenshot differs, but the point is the same; actual screenshots from an English Windows are welcome as replacements).
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/gwksb.png)
Click the keyboard you don't want, in this case likely "United Kingdom", and then click Remove.
![enter image description here](https://cdn.statically.io/img/i.sstatic.net/qVhPJ.png)
That's it. No need to restart or anything. The unwanted layout is gone.
Of course I can't say if this will help you, but it sure did help me.
And sorry for the messy answer with screenshots in Danish. I hope it can be understood anyway. It would likely take me 45 minutes more to switch the interface language of Windows to English, add the exact same keyboard layouts as you had, take the screenshots, and then change everything back again afterwards, and then I likely wouldn't have written this at all. Please forgive me. 🙂