Thanks Evgene that was actually useful and it reminded me that there is something in one of your tutorials as well.
Turns out though the problem was that a bit of javascript was failing. I have some "global" variables being defined within one of my scripts. In here I defined 2 variables:
var mapOptions = { mapTypeId: google.maps.MapTypeId.ROADMAP };
var directionsDisplay = new google.maps.DirectionsRenderer();
But the app has no internet connection so therefore (and I'm assuming stuff here) it hasn't/can't download the javascript for google maps api. Because of that any reference to google.maps..... etc is undefined and the script was stopping and not loading fully but when it did have a connection everything ran fine.
Am I right when I say that the google api's are downloaded from the web and not included in the app ? If so are there more javascript or css files downloaded when the app starts ? This may well explain some other issues I have.