Don't worry too much--Mexican food in the US and Mexico is most likely completely unrelated to what you get in the UK--incidentally, no "curry" in it at all--for a lot of dishes, the only spiciness comes from the salsa, which is applied to the food at the discretion of the eater--Also, peppers are Chiles," Chili" is a meat and pepper stew that may or may not have beans in it(we had a fairly heated discussion about this here, not that long ago), and is really American rather than Mexican--