It always makes you look keen if you phone them up beforehand - so it could work in your favour if you phone to explain that you really don't want to miss the interview and could they arrange something when you come back?
You mean when they e-mail me to arrange an interview? Or a pre-emptory phonecall? Applications close in two days, so they should mail me before I go away, hopefully...
Pre-emptory is probably best. The phone call, if done properly, will come off as very professional, plus you are somewhat standing out by putting your foot in the door and proving your interest and loyalty to the job.
It might be worth making a pre-emptory call - it can only make you look keen and organised. And it would set your mind at rest too.