UK PC keyboard has wrong key mappings.

In the system preferences-> Keyboard -> input sources I have British and British - PC. I need the first one as its the binding for the internal keyboard, and the second one was my attempt to get the PC keyboard working. No matter which I select in the menu bar to be active, the keys are wrong.

I have 3 bog standard PC keyboards, 2 dells and a HyperX gaming keyboard. All work with the Mac, and all have the same incorrect key mappings. They all have the same keyboard layout, the same as 99% of all UK keyboards.

In the top left on all 3 keyboards is pipe and a single quote. When I hit this on the Mac I get `~ or \| depending if I use "british" or "british PC". Neither are correct - both fix one of the two chars.

On the two keys to the left of enter on the same row as L, I have @' and tild pound. What I get when I type these is '" and \|

The bottom left key is pipe and backslash. This comes out as `¬ If I select "british pc" and §± if I select "British"

Because the mappings are so wrong, I find it very hard to use the mac. E.g. I dont know how to get the At key, which means I cant type in any email addresses. Finding tild is something of trial and error. There is no way I am going to spend £100+ on a mac keyboard when I have £100+ keyboards with cherry red switches.

Are there any UK people out there who have solved this issue?