[There's a lengthy delay in replying while he figures out all this business with boxes, but when it does arrive it's very neatly handwritten]
Thank you! It does feel strange to be here again. You've been back and forth enough times that I expect you understand it. Slightly adrift, but glad to see my friends again.
Sirius seems to like the class. At least by the look on his face when I told him I was going to put a stop to it. Look, I know I said I didn't agree with any of it but it seems unkind to disappoint him. Would you consider another arrangement? That is, that he keeps attending, but that I go and sit by him and observe and make sure all is well? It isn't you that I'm worried about, it's his classmates.
Really it was the other chap who gave out the boxes and not me. They're very clever, aren't they? Very advanced transfiguration. I wouldn't know how to do it! It's my best subject, but those localised and directed vanishing spells must be so difficult. I suppose I ought to carry on with the system. For his sake, if he went to all that trouble, and because it seems far more sensible than writing long letters on the telephone.