Thanks for your help Noah, I ended up asking my web-guru friend who gave me this genius answer, assign a class to it and then you can control it through CSS eg.
function addFeatureLayer() {
            var featureLayer = new FeatureLayer("http://services.arcgis.com/7eMCKfEPV8BkFVLQ/arcgis/rest/services/PubsFaceWatch/FeatureServer/0", {
                id:"featureLayer",
                styling:false,
                dataAttributes:["Incidents"]
            });
   console.log(featureLayer);
            if (featureLayer.surfaceType === "svg") {
                on(featureLayer, "graphic-draw", function (evt) {
    className = "svgClass";
                    // set the data attribute for the current feature
                     
     evt.node.setAttribute("data-class", className); 
                });
            } else {
                alert("Your browser does not support SVG.\nPlease user a modern web browser that supports SVG.");
                dom.byId("legend").innerHTML = "Your browser does not support SVG.";
            }
            map.addLayer(featureLayer);
            return featureLayer;