These aren't British, and they don't annoy me, I just don't get them. Anyway, fixing and cutting when used like 'I'm cutting out the lights' and 'I'm fixing to get some ice tea.' I just don't get how they fit in those sentences. When I lived in South Carolina, no one told me that cutting out the lights was just turning them off. I thought my roommate was going to actually tear open the wall, get wire cutters, and actually cut the wire to turn the lights off.
I say so many of these phrases though, it's embarrassing.