STOKES & SONS, SYDNEY:
New information in Trove (https://trove.nla.gov.au ) has explained what happened to Stokes & Sons Sydney office, running from around 1900.
This shows that Thomas’s full name had been Thomas William Stokes (He had died in 1910). A partner had been taken on.
Either the sale had not gone through, or Muller bought the firm himself, before changing the name.