Welcome to the Bunnings Workshop community @Clive. It's great to have you join us.
It would be fantastic to hear more about your project and understand what community members can help with. Are you looking for recommendations for the right screws for this project? What is the size of the area you're working with?
It would be great to see a picture of your space too so we can follow along with your project updates.
Thank you for sharing your question about ground screws.
Which part of your upgrade will you be using the ground screws on? Is it being used as a support and what kind of loading stress will you be putting on it? There are several types from Dynabolts to Chemical Type Anchors that can be used depending on your needs. Would it be possible for you to post your plan? This will allow us to give you a more comprehensive recommendation.
Please keep us updated, we look forward to seeing your plans.