Hi Neutron 16,
as with many things in life, turning it off and turning it on again solved the problem. Well actually turning it off and again three times, as I transported it various places seemed to do the trick. This afternoon when I turned it on again it suddenly decided it would be American, although I have had to remind it with one document. On the plus side I'm now learning to spell American-like.
Thanks for your help though! If I have any more problems I'll definitely give it a go!