Google Maps smartinfowindow position

I am trying to change the infowindow in Google maps to the smartinfowindow but for some reason the position of the infowindow is wrong. I never had this issue with the standard infowindow, only the smartinfowindow.

I have found that if I remove position: relative from the map canvas using Firefox inspector the map moves to the top left of the window and the viewport seems to extend to the width of the window which results in the smartinfowindows then being in the correct position.

So is there something I'm missing?

I create the markers with the following:

for (var i = 0; i < data.locations.length; i++) {

    var dataPhoto = data.locations[i];
    var latLng = new google.maps.LatLng(dataPhoto.latitude,dataPhoto.longitude);

latlngbounds.extend( latLng );

var marker = new google.maps.Marker({
    position: latLng,
    icon: 'http://www.irishcottageholidays.com/images/cottage1.png'
}); 

listenMarker(map,marker,InfoWindow,dataPhoto.mID)

    markers.push(marker);
}

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And then to create the smartinfowindow:

function listenMarker (map,marker,InfoWindow,mID){
google.maps.event.addListener(marker, 'click', function() {
    load_content(map,this,InfoWindow,mID);
});

function load_content(map,marker,InfoWindow,mID){
    var $j = jQuery.noConflict();
    $j.ajax({
        type : 'GET',
        url : '/ajax/map_popup.asp',
        data: {
            mID : mID
        },
        success: function(result){
            new SmartInfoWindow({position: marker.getPosition(), map: map, content: result});
        }
    });
}

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Originally I created the infowindows using:

InfoWindow.setOptions({
    disableAutoPan: true,
    maxWidth: 280
});
InfoWindow.setContent(result);
InfoWindow.open(map, marker);

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And this worked but now I've changed to the smartinfowindow, it loads the infowindow but not in the right position.

Below is the image of the smartinfowindow after clicking on the circled marker:

Here is the page when I have removed position: relative from the map canvas:

Thanks for all help in advance.