How do I set a default keyboard layout in Xfce?

[olop1]

I posted this in Beginners questions as I hadn't realised there was a separate Xfce sub-forum but unfortunately I have not had any relevant replies.

I have a new new wireless keyboard which has a slightly different to the laptop keyboard.

Previously I had the keyboard layout as English (UK) which works for the laptop. The new keyboard needs English (US) otherwise some of the keys are wrong (@ especially). So I added that to keyboard layout plus another language and put English (US) at the top of the list.

Unfortunately every time I restart the computer it reverts to English(UK) and I can only get it on English (US) when I delete English(UK) entry. I am guessing this is also to do perhaps with the language setting?

I found in Settings Editor under keyboard-layout and keyboards it mentions a Property - Default - but Type says Empty and then Locked and Value have nothing.
XkbLayout under Type has String and then Value us,gb,th - for the 3 layouts.

I am guessing there is a fairly simple way to set the default keyboard layout but I have no idea how to go about that.

I tried to add the words "String" and "us" in the Default line as Type and Value but that does not seem to have changed anything - I did not tick the locked box.

I have also realised that I also don't know how to switch to the Thai keyboard layout if I need to use it.

Can anyone help please?