Hermione was staying in the back room, but she'd told the twins she was meeting with Neville and so Fred sent George off to do the shopping - didn't fighting a war in your spare time mean you didn't have to do the summer homework? He'd have to tease Ronnikins about that later - and spotted Neville as soon as he came in.
"Mister Longbottom," He said as he slid down the stairwell toward him and then started to guide Neville back up the stairs and toward the counter - and coincidentally the back room behind it - "Just got that order you put in. It's in the back."