I think I've found the answer, was really simple and I feel quite dumb! Just requires a single to change to the javascript.
Original:
<script type="text/javascript">
$(function () {
$(".drag_drop_grid").sortable({
items: 'tr:not(tr:first-child)',
cursor: 'crosshair',
connectWith: '.drag_drop_grid',
axis: 'y',
dropOnEmpty: true,
receive: function (e, ui) {
$(this).find("tbody").append(ui.item);
}
});
$("[id*=gvDest] tr:not(tr:first-child)").remove();
});
</script>
Fixed:
<script type="text/javascript">
$(function () {
$(".drag_drop_grid").sortable({
items: 'tr:not(tr:first-child)',
cursor: 'crosshair',
connectWith: '.drag_drop_grid',
axis: 'x, y',
dropOnEmpty: true,
receive: function (e, ui) {
$(this).find("tbody").append(ui.item);
}
});
$("[id*=gvDest] tr:not(tr:first-child)").remove();
});
</script>
All that's needed to change the axis from y to x,y