There's probably no need for the British spelling of "apologize" here, as this sign is posted at a gas station in New York. But since I'm one of those silly Americans who is totally charmed by all things British (at the top of the very long list: Muse, Refreshers candies, and Alexander McQueen), I'm OK with letting that spelling slide.
However, I can't let the other thing slide. You know, that whole "upgrading ourself" thing. It's one of the more absurd errors I've seen lately, and I'm thrilled that this is not a gas station I regularly pass by during my day-to-day travels...seeing this goofy sign every day would seriously drive me nuts. Like, nuts to the point of going out there in the middle of the night and taking a chainsaw to the bottom of the sign so that the writing on the sign ends with the word "upgrading." At this point I don't care what they're upgrading, and I don't care if the sign specifically mentions what they're upgrading--but that "ourself" really needs to go.
Thanks to JOHN B. for spotting this crazy sign!