Google Maps loads to the right of the marker! - google-maps

Question

For some reason, Google Maps is loading the following map with the marker to the left - I have no idea why.
I've got this page in an iFrame, which is getting loaded in a lightbox, but an issue is it doesn't load the map exactly ON the marker, it's always down to the left.
<link href="https://code.google.com/apis/maps/documentation/javascript/examples/standard.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="https://maps.google.com/maps/api/js?sensor=false"></script>
<script type="text/javascript">
var geocoder;
var map;
function initialize() {
geocoder = new google.maps.Geocoder();
var latlng = new google.maps.LatLng(-0, 0);
var myOptions = {
zoom: 15,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
}
function codeAddress() {
var address = '1 Dover Street, London, United Kingdom';
geocoder.geocode( { 'address': address}, function(results, status) {
if (status == google.maps.GeocoderStatus.OK) {
var latlng = new google.maps.LatLng(results[0].geometry.location);
var myOptions = {
zoom: 15,
center: latlng,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
map.setCenter(results[0].geometry.location);
var marker = new google.maps.Marker({
map: map,
position: results[0].geometry.location
});
} else {
//alert("Geocode was not successful for the following reason: " + status);
}
});
}
</script>
If anyone could let me know why it's doing that, that would be great!
Thanks!