Independent inspection

Hi all, I'm looking for some advice regarding my solar and battery installation. I have a number of concerns, ranging from installation quality to what I believe may be safety issues.

They have addressed a number of the issues, however progress has stalled. Before escalating things formally, I'd like to get an independent inspection carried out so I have a full, professional assessment of the problems. My intention is to give the installer every opportunity to put things right, but as I'm not qualified to identify all the issues myself.

My confidence in the installer has hit rock bottom, so I feel this is the most constructive approach to take before taking this further.

Has anyone been in a similar situation, or can anyone recommend how to go about this?

Thanks in advance.