Even though English UK is set as the language to spell check in! It's really annoying me and I can't work out how to change it. I tried adding US English and deleting it, but that didn't work. Have checked the language settings in Windows even.
I did restart Word between changing the options and it makes no difference. If I pull up the spell checker, it even says at the top "Spelling and Grammar: English (U.S.)" Yet in the options, it clearly shows English (U.K.) as the selected language. 
If anyone knows how to fix this I would be eternally grateful, as it keeps autocorrecting stuff and I keep missing it, and I'm on an English course, it's not going to look great if I keep handing stuff in with Americanised spellings all over it...