Welcome to the Bunnings Workshop community @stefanwright41. It's fantastic that you've joined us and many thanks for your question.
The most permanent solution is to locate your timbers behind the eaves sheet and screw directly into them. They can often be found behind the sheets' joins and are given away by the nail locations. Alternatively, I would advise spring toggles as the next best option because they grab the sheet from behind.
Please let me know if you need further assistance or had questions.