The Doctor travelled to Diagon Alley the next day. Idris had been parked a street away from the Leaky Cauldron where McGonagall would lead them for a tour around the Alley. The Doctor presumed this was due to the fact she had no prior knowledge about the underground Carrionite society.
She was probably meeting humans with higher than normal artron energy levels who were being introduced to this world. Did that mean all time travellers could use Carrionite magic? Her companions might benefit from learning it then - they could at least defend themselves better.
She read the letter once more and realised she didn't have any money. Hermione's savings had been used up so she needed to give them something else. Perhaps if she brought something valuable? Painite was still rare wasn't it? Humanity hadn't colonised Painites yet had they? She had some pure Painite crystals she'd bought.
Deciding it was better than nothing, she took a three medium sized ones from her collection. She then sprinted to the Leaky Cauldron - she didn't want to be late! She arrived just before McGonagall herself who sent her a disapproving look. She was soon introduced to the other 'Muggle-Borns':
Kevin Entwhistle, Justin Finch-Fletchey, Anna and Anne James, Kellah Johnson, Roger Malone, Leo Miller, Sally-Anne Perks, Dean Thomas, Alice Tolipan and (finally) Lisa Turpin.
The Doctor introduced herself as Hermione Granger - McGonagall probably wouldn't let her claim the name Jane Smith. For once in her life she kept quiet - she didn't think she could battle thousands of Carrionites at once if they got offended. People tended to do that when she opened her mouth.
"Right" McGonagall said "First we will head to Gringotts - the Wizarding Bank. Have you all got your money?" They all nodded dutifully. "Good. The bank is run by goblins. Please do not stare at them - they will not take it kindly. I suggest opening a vault. The goblins will need a drop of blood for this. I hope none of you are scared by blood."
McGonagall seemed entirely oblivious to the way Justin gulped and the paling of Lisa's face. She carried on brusquely "Come on then!" With that matter of fact introduction, their group was led to a seemingly ordinary brick wall. The group frowned unimpressed. They seemed to have wanted a more - magical entrance.
Knowing things weren't always what they seemed like, the Doctor chose to observe the strict woman. The professor tapped the brick that was two across and three up from the bin - clearly it had been placed where it was deliberately.
The bricks appeared to fold away to reveal a bright, bustling street. Leo whistled at the unexpectedly sight. The Professor was already miles ahead of them: "Come, we haven't got all day.", she snapped when she realised how far back they were. She didn't seem very patient and the Doctor wondered how she could be a teacher. Or rather why. As they jogged to catch up to the Professor, the Doctor reflected that maybe she didn't need to be.