DrAzzy:
If you looked at the pinout charts as suggested, you'd find something like this:they show the arduino pin number, the port number (eg, PC2), the analog pin number (if applicable), list any special functions, all showing which physical pin that corresponds to
Thanks - the pinouts I have been using / seen have never included the arduino pin reference as per the one you posted, which is why I have been struggling.
Having done another google search (the same one I think I did the first time - 'atmega 328pu tqfp pinout' a few of them have the arduino pins listed, just by chance I must have only clicked on the ones that didn't or I would not have asked the question!
Thanks for your help