Thanks for your reply Andrew,
Structural Pine = Framing Lumber, makes sense. Some of my fellow modelers here have also advised against treated pine for possible toxicity reasons, although reading local literature the treatment method is no longer a health issue. I believe Arsenic was used in the past. Untreated structural Pine is available from Timber suppliers, it is Kiln dried Radiata Pine, I will follow that path.
Regards,
Alan Ford