How can I change the starting location of Google Maps showed in my website?

I have a simple Website that displays a google map. My issue is that at the minute it starts in New York and I want it to start in Lond instead. How do I that?

In my HTML page I have

<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyBsXUGTFS09pLVdsYEE9YrO2y4IAncAO2U&amp;callback=initMap" async defer></script> `` And <div id="map" class="map height-400"></div> And I believe this is the java script it uses -

"use strict";

This is the gmap.js I am using which I believe picks the location. 
window.initMap = function() {
  var customMapType = new google.maps.StyledMapType([
    {
      stylers: [
        {'saturation': -100},
        {'lightness': 50},
        {'visibility': 'simplified'}
      ]
    },
    {
      elementType: 'labels',
      stylers: [{visibility: 'on'}]
    },
    {
      featureType: 'road',
      stylers: [{color: '#bbb'}]
    }
  ], {
    name: 'Dublin'
  });

  var image = new google.maps.MarkerImage(
    'img/widgets/gmap-pin.png',
    new google.maps.Size(48,54),
    new google.maps.Point(0,0),
    new google.maps.Point(24,54)
    );

  var customMapTypeId = 'custom_style';

  var brooklyn = {lat: 41.850, lng: -73.961};
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 6,
    scrollwheel: false,
    streetViewControl: false,
    mapTypeControl: false,
    center: London,
    mapTypeControlOptions: {
      mapTypeIds: [google.maps.MapTypeId.ROADMAP, customMapTypeId]
    }
  });

  var contentString = '<div id="content">'+
    '<div id="siteNotice">'+
    '</div>'+
    '<h1 id="firstHeading" class="firstHeading">Brooklyn</h1>'+
    '<div id="bodyContent">'+
    '<p>277 Bedford Avenue, <br> Brooklyn, NY 11211, <br> New York, USA</p>'+
    '</div>'+
    '</div>';

  var infowindow = new google.maps.InfoWindow({
    content: contentString,
    maxWidth: 300
  });

  var marker = new google.maps.Marker({
    map: map,
    clickable: true,
    icon: image,
    title: 'Brooklyn',
    position: brooklyn
  });

  marker.addListener('click', function() {
    infowindow.open(map, marker);
  });

  map.mapTypes.set(customMapTypeId, customMapType);
  map.setMapTypeId(customMapTypeId);
}

This whole API and process is very new to me and I appreciate if anyone has an answer! Ty!