Didn't realise there was a "secondary" fuse.
When I wired up my earth, if I remember correctly there is another screw further up that support bracket nearer to the dash board metal support framing, that is the one I used.
Note : I had a mate who purchased a new dash cam and in his hurry to see if it worked rather than using the supplied lead, connected it direct to 12 Volt - resulting in a bricked dash cam........make sure when testing that you use the supplied lead(s)......It only needs a 5 Volt supply