It seemed she had guessed right for the goblin simply looked at her lazily and asked her for some of her blood. They weren't sneering which she considered a success. Her fellow students weren't having such pleasant encounters. Roger Malone seemed completely terrified of the Teller he was conversing with.
"Why?" she asked. Blood had some properties - the Cybermen had attempted to control people through it. Granted their instincts proved to strong - and the Doctor shared them, but she still had to be cautious. Sooner or later, someone was going to find a way to control humanoids by their blood. She wasn't looking forward to it. The goblin did not seem to appreciate that much: "Unless of course you would prefer not to open an account."
Giving him an apologetic (hopefully) smile, the Doctor took the offered blade and cut her finger. The goblin let it drip onto the parchment that lay between them. Ink the colour of her blood materialised on it. The Doctor wondered if it was infused with artron energy or if the goblins used a different type. Unfortunately, she wasn't allowed to touch, lick or otherwise interact the parchment. She thought it would probably affect her results and she didn't want to cut her hand again.
The Doctor, who was busy looking around the place, didn't notice the shock on the goblin's face as he read her results. He had expected the normal results for Muggleborns, not what was written on the parchment. She did notice, however, when he looked at her and whispered disbelievingly, "The Oncoming Storm?"
"Of course not", she lied unconvincingly, "Whe-Where did you hear that?" she asked curiously. How did the goblins recognise her title? It had presumably come up on the parchment that she could no longer see but that didn't explain the look on the goblin's face. The Doctor completed her transaction as slowly as she dared. She was trying to pretend she wasn't shaken.
It turned out painite was still quite valuable - one 24 carat piece was worth 240,000 galleons. As she had three, she left the bank with 719,170 galleons in her vault and 830 in her purse. The average cost of school supplies was about 820 to 830 galleons so she supposed poorer families got some sort of financial aid - at least the Pureblood ones. 820 - 830 galleons was roughly £4100 - £4150 which was rather expensive for the time.
Shaking her head as though it would help her clear her thoughts, the Doctor waited patiently for the other students to finish. When she said patiently, she meant her fiddling was going unnoticed. The Doctor really wanted to find out more about these goblins but scanning them with her sonic would just be rude. Finally, the others finished and she could get out of there.