Builders not completing tasks after settlement

Hi,
We have recently settled on a property and the builder has some minor works to conclude which were discovered as a result of a building inspection performed prior to settlement.

Some of the works have been concluded whilst some others remain outstanding. In one instance, I replaced a security gate lock myself as vandals were entering the property whilst I was awaiting the builder to repair it.

So far (~2 weeks have passed) the builder is showing extreme lethargy in making the necessary repairs, despite repeated calls from myself.

I am interested in hearing from others with similar experiences.

Perhaps the following questions would be appropraite:
1/ Have you performed/arranged the repairs yourself and forward the costs onto the builder?
2/ Has the builder followed through on post-settlement outstanding repairs?
3/ Is there a legal approach to take that would be appropriate in these circumstances, or is there other government bodies that protect consumers in these circumstances?

Look forward to your posts!