Yeah Qld too, Np with the help,
I might also suggest seeing if that rod has been pushed in too far or it's out too far and has just been displaced in a way that it can't build vacuum inside the booster, so it may be ok, and just needs to be adjusted so the internal valve closes again to build vacuum.
This could maybe happen during removal or if the pedal was pressed too hard with or without vacuum in the system, I'm not sure but it's worth a try playing with it to see if it's just out of normal range.
Could help without vacuum or with vacuum, just have to try what gets it moving and test for that leak In between or while vacuum is applied, the leak may end up going away, if you plan on replacing the booster, there's no harm in trying and if it doesn't work them maybe the booster diaphragm is busted or something else at the back side.