Hmmm, just realised Sydney doesn’t have any shrines as such to Our Lady of Lourdes, although of course there’s a parish and church named after her. That seems to count, and is actually do-able for me.
So apart from the normal conditions of a plenary indulgence I just need to visit, pray the Lord’s Prayer, the Creed and any prayer to Mary (assuming I can’t find the actual Jubilee prayer online somewhere). Too easy!