You can take bumper and slam off together BUT you obviously still need the grill removed to get the bonnet release cable out (and the hockey stick clips unless the grill tabs are already broken lol). For the extra couple of minutes its just as easy to remove the bumper separately. Also means you can get the hockey sticks out with the grill without snapping all the bottom lugs off (squeeze tabs together under headlights).
Those 2 'spare' 13mm nuts look like the ones from the gearbox mount to bracket.
Those 2 'spare' 13mm nuts look like the ones from the gearbox mount to bracket.