The link below is to a copy of The Local, issue 102 from 2017. Once you are in the reader, open the magazine by clicking the arrow on the right. You will come across, on p3, an article about 'the autograph' on the wall and also the answer to Q21. The Local is a weekly news magazine of the Central Highlands of Victoria. Worth a read...
https://issuu.com/dhslocal/docs/the_local_issue_102_july_17__2017