This search was referred to me from several sources. Thank you to my network.
John C had posted the following on line:
“ I would like to return this WW1 RETURNED FROM ACTIVE SERVICE BADGE to the family of C HOGARTH - it may have been found in the Eastern Suburbs of Sydney by my late father himself a WW2 Vet”
These are the pictures of the RAS badge.
Based on John’s description of where the badge was found and the other information available on line, I narrowed it down to the only person who fit the bill. This was 7716 Claude Horatio Hogarth. His service record can be found here: https://recordsearch.naa.gov.au/SearchNRetrieve/Interface/ViewImage.aspx?B=4760965
Not long after working out who Claude was I found a direct descendant on Ancestry. Within 5 minutes of sending a message to the family I was able to connect John and Kerryn from the Hogarth family.
A nice result just before Anzac Day. The returned medal tally is now 2611.