Visit this Government of South Australia website

 

https://secure.cbs.sa.gov.au/OccLicPubReg/LicenceSearch.php

 

Type in the license number of the builder and a first or last name and be sure they are licenced to do the work you need done. 

 

Some bathroom renovations require building works, and hence someone who is only licenced for 'wall or floor tiling' may not really be competent to do the full renovation.