The Vampirates series is set five hundred years in the future, in a world much more watery than the present-day one. From the synopsis of the first book:
The year is 2505. The oceans have risen. A new era of piracy is dawning.
At the start of the series, our heroes, Connor and Grace Tempest, have lived all their lives in Crescent Moon Bay. Do we know where this is meant to be, in terms of real-life geography? Even though "the oceans have risen", presumably any piece of dry land in 2505 is also on land in the present day.
To put it another way: where in the world are Grace and Connor from?