If no adverse record appears, does that mean the builder has a clean history?

Not necessarily.

A search may show that no adverse record was identified in the particular public register you checked, but that does not prove the builder has never been:

• the subject of a complaint
• involved in a building dispute
• required to rectify defective work
• investigated by a regulator
• involved in previous construction defects
• subject to action that is no longer publicly displayed.

A more accurate conclusion is:

No adverse record was identified in the public registers searched at the time of the check.