After my previous post regarding my struggle to find a Linux laptop in Australia, I have now been given a suggestion that may solve the problem. While waiting for my daughter to finish dance class, I stopped into a company called TopBit Computing. I have never dealt with them before, but the sales guy seemed to know his stuff.
When I listed my requirements, he suggested Pioneer Computers, who manufacture laptops locally and will pre install Ubuntu Linux or Windows. The systems they sell are very configurable, but I did not jump in straight away, as this is a company I had not heard of previously. I will do some investigation in the coming days.