Aaaagh! Ruddy Window 8!!!
From the Microsoft website:
"Your default keyboard layout or input method is the one that’s automatically used with the language you see Windows in (for example, the QWERTY keyboard for British English). If you want to keep your Windows language the same but use a different keyboard automatically, follow these steps:
Open Control Panel by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Control Panel in the search box, and then tapping or clicking Control Panel.
Enter Add a language in the search box, then tap or click Add a language.
Tap or click Advanced settings.
Under Override for default input method, choose the keyboard layout or input method that you'd like to be your new default, then tap or click Save"