Moony, back when I left, I opened a small vault for Junior, in case I needed him again. There were only a couple Galleons in cash, but much more to the point there should be copies of the transcripts and other sundry things you might need to make his identity more credible. I hid the key in Wormtail's mother's back garden, under the shade elm on the treehouse side. Do you think you could get to it?

If not, or if it's gone for some reason, I daresay Professor Slughorn has a copy of the letter of recommendation he wrote. And Minerva might be surprised to find some of his records in the old school files. We could of course start from scratch if necessary, but why bother if the parchment has already been inked?