test.html

<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8' />
    <title>Restrict map panning to an area</title>
    <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
    <script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.js'></script>
    <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.51.0/mapbox-gl.css' rel='stylesheet' />
    <style>
        body { margin:0; padding:0; }
        #map { position:absolute; top:0; bottom:0; width:100%; }
    </style>
</head>
<body>

<div id='map'></div>
<script>
mapboxgl.accessToken = 'pk.eyJ1IjoidGFzdGF0aGFtMSIsImEiOiJjamZ1ejY2bmYxNHZnMnhxbjEydW9sM29hIn0.w9ndNH49d91aeyvxSjKQqg';



var map = new mapboxgl.Map({
    container: 'map',
    style: 'mapbox://styles/tastatham1/cjovehd7n0a812rpbzz0n5ke2',
    center: [-2.594555,51.450625],
    zoom: 11,
});


map.addControl(new mapboxgl.NavigationControl({ //Add navigation control - North Arrow
            position: 'top-right' // position of navigation top-right
        }));  
  
map.addControl(new mapboxgl.FullscreenControl()); //Add full screen mode

map.addControl(new mapboxgl.ScaleControl({ //Add scale bar
    maxWidth: 300,
    unit: 'imperial'
}));
</script>

</body>
</html>