Remove the white plastic bracket from the fuel filler. 

Unbolt and remove the factory clamps from around the fuel filler. 

Undo the hose clamp from the fuel filler and detatch the fuel filler from the hose. 

Fasten the M2 fuel filler mount on to the headboard using x2 M8x25 button heads with spring and flat washers. Bolt the fuel filler to the M2 mount using x2 M5x16 button heads with a washer on the back and nylcos. 

Once your fuel filler is bolted to the M2 mount, reassemble the hose to the fuel filler and fasten the hose clamp. 

Take the factory fuel filler mounts and fasten them back around the fuel filler. 

Take the fuel filler bracket and fasten to the factory mount using M8x25 hex heads with a washer on both sides and a nyloc.

Now bolt the fuel filler bracket to the tray using M8x25 hex heads with a washer on both sides and a nyloc.

Your hilux fuel filler should now be looking like this. 

Your Hilux fuel filler should be looking as so

Your Hilux fuel filler should be looking as so

Your Hilux fuel filler should be looking as so