Learning what Heather's disability was, didn't bother Andrew at all, and it certainly wouldn't deter him from getting to know her better, like he would with any other ordinary person. In fact, it was kind of interesting… He wondered what it was like, "seeing" or rather, sensing things from Heather's perspective. 

"Glad to be of assistance," Andrew said with a jolly tone, stepping out into the street as he guided Heather along. His focus then shifted to steering the both of them carefully yet swiftly across the center lane of traffic. Once they reached the other side of the street, Andrew felt at ease to pick up their conversation again.

"So, you're from America? And you just moved here, to England right?" He gave a pause in between for Heather to answer each question. "How long have you been here? Where do you live?" --He followed up quickly with-- "I'm from Romford, if you know where that is. Havering. It's about an hour's drive from here. I take the Floo though, if you know what that is. Pretty much, you just step into a fireplace, throw down some Floo powder, say the name of the place you want to go to, and then poof! You're there! It's like teleportation. That way my parents don't have to drive me here every time."

A little ways farther, and they'd be at the post office. An airy building lined with plenty of windows, home to dozens of owls, some of them perching for a rest, but mostly a steady stream of them swooping in and out with parcels and envelopes clutched in their beaks and talons. Andrew had to duck slightly to avoid getting whacked in the head by a box-shaped package, as a large brown owl zoomed past him on its way out. 

Once Andrew got his hands on a slip of paper and a quill pen, he'd turn to Heather and say, more or less uncertainly, "You can write though.. uh, right?" He wasn't sure how near-sighted she was, if Heather could see things up close. Either way, Andrew was prepared to write the note for her, addressing it to Grandpa Bob, letting Heather's guardian(s) know that the pair of them would be waiting at the Magical Menagerie. Andrew would write down his own name too, first and last. In case Heather's folks wanted to scan his identity or something. 

Andrew would then scribble down a separate note for his parents as well, letting them know that he had purchased his vials and would be home a little late, since he was spending time with a friend.

He'd pay a few knuts to have the two owls delivered, and then Andrew and Heather would be on their way, to the pet shop.