thule bike rack - 3 bikes
tow ball mounted. very easy to use and secure. refer https://www.lpl.com.pt/resources/product_pdfs/970-3.pdf you need a key and can get at ebay around $20 you also need a adapter ( https://www.gumtree.com.au/s-ad/canberra-city/bicycle-parts-and-accessories/970-3ap-thule-3-bike-rack-970-metal-mounting-plate/1176509729 )