Ron wasn't in his new robes yet because he'd point-blank refused to wear one of the spare pairs that were set aside in Goyle's size. This meant he had an uncomfortable trip to see Madam Malkin in his lunch break, but at least he could avoid the dreaded magenta for his first day as part of the business.
Having told him to call if he lost a finger, George had left Ron to get to grips with the quirks of the till and that was where he was when Goyle finally arrived.
"Yeah, I am meant to be here. And George is out back working on something."