// Doesn't work
SeatingPlanEditor.seats[index].point.target.setStyle({color: '#0000cc'});

// Also doesn't work
SeatingPlanEditor.seats[index].point.target.setStyle({color: '#0000cc'});

// Also doesn't work surrounded by
SeatingPlanEditor.map.removeLayer(SeatingPlanEditor.seats[index].point);
// set the style either way as above
SeatingPlanEditor.map.addLayer(SeatingPlanEditor.seats[index].point);