Chris - yes thanks I appreciated that - it was more about the slightly conflating measures.
So now having looked into an engineering guide, the NOCT, which is the typical operating temperature is typically 45 degrees plus or minus a few - and that is the typical and therefore optimal operating temperature of the cells in the panel when operating.
Therefore the optimal efficiency of the panel and cells is its NOCT temperature with the offset of Pmax applied at 45 degrees (or whatever its optimum operating temperature is) from 25 degrees
So to look at the panel efficiency with temperature one needs to look at the cell NOCT and Pmax combined so I have now understood. So you can see a panel with a lesser Pmax efficiency can actually be more efficient overall at the average operating temperature (NOCT) of usually 45 degrees… which is what I was concluding previously which appeared slightly conflicting.
But having looked at a few worked examples there doesn’t seem to be huge variations between panels from what I have seen. Therefore looking at the operating temperature efficiencies between 25 and 45 degrees one sees variation between 92 and 96% across different manufactures and construction types.
The bottom line, though the PV panel and its cells generally benefit from being cooled or cooling air flow, some panels are more optimum for hotter temperatures and others for cooler, but not significantly so from what I can see.