Thanks for the suggestions.
I have no data to backup my thoughts, but I am beginning to wonder if there is a difference between Raspberry Pi’s throughout the world. My Pi’s (Australia) are all made in China, I assume most Pi’s sold in Europe are made in UK (Wales?). Could this be a reason why WIFI (Access Point) and Bluetooth seem to perform better for some than others? Different chips? I would think that a RPi3 with on board WIFI and Bluetooth running Max2play should perform the same anywhere in the world, but I can’t seem to get somethings working as they should? Just a (stupid) thought.