Hi Nick ...
WebpageIcons.db is your Home folder not root level.
Open a Finder window. From the Finder menu bar click Go > Go to Folder
Type or copy paste the following:
Click Go then move the WebpageIcons.db file to the Trash...
Quit and relaunch Safari. It may take a day or two for your favicons to re populate.
/Library < root
~/Library > home
The ~ (Tilde) character represents your home directory.
message edited by: cs