Hi Mark,
Reading the description above carefully, I understand that the primary issue is about the "google authorship code".
You have ever used the Paypal gadget to insert the code and it did work before. I'd like to confirm whether the Paypal gadget works now or you just mean the Paypal gadget does not work now.
I've no idea about what code you are using, and we could provide limited assistance on code because our forum does not focus on the code field. The dedicated support forums MSDN and TechNet are staffed with engineers who can provide professional assistance on code. You can post the question there and they will help you with the code.
In addition, I've noticed that some community users have raised issues about the Paypal gadget when they use SharePoint Online 2013. And there is a popular and positive community member who suggests using the Embeded Code tool provided in SharePoint 2013 and wrapping the Paypal code with a closing and opening form tag:
</form> <!-- your PP code here <form>xxxxx</form> --><form>
Here are the threads for your reference:
http://community.office365.com/en-us/forums/148/p/160018/454017.aspx
http://community.office365.com/en-us/forums/172/p/162363/463478.aspx
http://community.office365.com/en-us/forums/148/p/188037/551971.aspx
@Mark, I'm sorry for any inconvenience that you have encountered but I suggest you provide the code that you are using and show us how you add it to your public site page. Some community members who have experience will share their cool ideas when they see your code.
We'll appreciate your understanding.
Regards,
Cherry