Metal roof and wall noise

Hello all - some time ago I did a post on a metal roof with no sarking. My warranties inspection has been postponed by my builder due to COVID-19 (which is fine).

My roof pops and makes noise when the sun comes out. But not only this, one of my walls (quads) makes noise as if they are coming unstuck from the skirting boards at the exact same time, every time. Does anyone know why? It is only in one wall of the house.

I had an independent inspector for all stages throughout my build. I was speaking to my construction lawyer about another matter not directly related to the construction of my home and mentioned the very loud noises. He suggested I get my inspector back (not a structural engineer) prior to my builder coming back. My inspector does not offer this service so I was wondering if it is still worthwhile getting a structural engineer out instead. I understand that metal roofs will pop due to thermal expansion and contraction but the wall and quad noise is another matter.

I am in Melbourne. Do you have any recommendations for an engineer? There are a few other things wrong with the house but nothing major (I hope).