In Scotland, "half a loaf" means a loaf. That is, "half a loaf" means an entire loaf; a whole loaf. I once had this explained to me at greatly repetitive length by a drunk man with an incomprehensible Glasgow accent, so you can be sure it is true.
Was curious about the etymology so looked it up. Seems like half-loaf referred to the fact that it weighed 2 pounds, half the standard "quartern" 4lb round loaf which was typically sold in quarters.