Customs duty.. Yu can dodge the 14.5% or what it is now by claiming the item is to suit a mk1 Cortina 62 model and the fees will drop to about 3%(historic) . This can be done even when it's landed and waiting. I did this on a crate load of stuff from Ian Harwood back in the early 2000s ,, tho he used to down the price on invoice and post the real one by air lol !
£544 squids is just over $1000au... But just! ! Maybe wait a month till its safe to buy for under a grand.