Custom adapter override find single record

I am creating an Ember application with a WordPress back end. I have a model called menu.

import DS from 'ember-data';

export default DS.Model.extend({
});

I am using the ember-wordpress add on, this creates a name space of

wp-json/wp/v2/

For my api calls.

I want to query WordPress for my menu which has the end point

"http://localhost:8888/ember-wp/wp-json/wp-api-menus/v2/menus/"

I am extending the WordPress add on adapter and attempting to set a URL with the urlForFindRecord hook so I can change the URL used when attempting to use findRecord in my route.

My adapter is named menu-adapter

import WordPressAdapter from 'ember-wordpress/adapters/wordpress';

export default WordPressAdapter.extend({
  namespace: 'api/v1',
  urlForFindRecord() {
    return `/wp-api-menus/v2/`;
  }
});

And then my route is

import Ember from 'ember';

export default Ember.Route.extend({

  model() {
    return Ember.RSVP.hash({
      project: this.store.findAll('project'),
      menu: this.store.findRecord('menu', 2)
    });
  }

});

However I get the error

http://localhost:8888/ember-wp/wp-json/wp/v2/menus/2 returned a 404

Which looks like it's not setting the URL correctly, I am not sure where I am going wrong.