Regarding the examination of George "Toppy" Hutchinson's handwriting, and the possibility of the wrong exemplar having been used, Russell Edwards recounts an incident involving the Swanson Marginalia in his book Naming Jack the Ripper.
Back in 1988, a photocopy of the Marginalia was sent to the Home Office, and this was compared to a known sample of Donald Swanson's handwriting by one of the forensic examiners, Dr. Totty. He came to the dramatic conclusion that the two writings were NOT written by the same person.
According to Edwards, this set off alarm bells, but it was eventually concluded that Totty had not been given a genuine, legitimate sample of Swanson's handwriting. An error had been made. Although the signature on the document was indeed Swanson's, and it did originate from his office, the main body of the report had been written by an amanuensis or secretary, so the comparison had been flawed from the beginning. Other exemplars were then re-examined and the Home Office felt that the Marginalia matched Swanson's handwriting. So reports Edwards. Similar deal?