Thanks for the answers guys. It looks like my concerns were justified. I’ll have to think again.
VK2him… I have found the USB 1-wire adaptor in Australia for less money (and somewhat quicker) and you can source some individual components(like DS18B20 temp sensors) but assembled instruments generally are not available. I have found that ordering what I need from Hobby Boards in the USA works well. Delivery usually takes about a week.
The mail costs can be steep however.
Regards
w0mbat