It looks like it's defaulted to US English. There'll be other settings to change as well.
Settings > Control Panel > Clock, Language and Region. Go through all the options and ensure you've got English United Kingdom selected, in particular try Add a language.
If that doesn't work, you're welcome to a US English keyboard that I've just replaced since it's been getting on my nerves for the reverse reason
Edit: Glad you've got it sorted now