Hannah shrugged, not really wanting to give a terribly lot of thought to that detail. She had no interest in going up there and Lucy wouldn't be up on any sort of roof without a million charms being in place, so she still had no strong desire to figure it out. Still, his suggestion made sense and was a good one.
"That could work, if it's the right size - and if it can be closed off to everyone but you, me, or Lucy -" She didn't like the idea of someone breaking into Neville's greenhouse because it was at the somewhat popular location of the Leaky Cauldron.