When your computers has shipped, click on the tracking link and their will be a number and then the number labelled "our delivery reference number". It should begin with 80, type this into apecode tracking and it will tell you where your mac is!
Bit of guidance though, the ETI is the date it is expected to get to a holding place, so for example my ETI was at Netherlands, it should then take between 1-3 working days after this.
Anymore questions and the apecode has its own mini forum which can be quite helpful.