JS error in WC checkout

Hello Duracelltomi,

I’m using your great plugin with WC integration and only data layer injection.
On the checkout page (https://wp-ok.it/checkout/) I have a JS error:

Uncaught ReferenceError: jQuery is not defined
    at (index):707

The code there is:

<script data-cfasync='false' type='text/javascript'>
	(function($) {
		if ( $( '.gtm4wp_productdata' ).length > 0 ) {
			for( var i=0; i<dataLayer.length; i++ ) {
				if ( dataLayer[ i ][ 'ecomm_prodid' ] ) {
					break;
				}
			}

			if ( i == dataLayer.length ) {
				// no existing dyn remarketing data found in the datalayer
				i = 0;
				dataLayer[ i ][ 'ecomm_prodid' ] = [];
			}

			if ( typeof dataLayer[ i ][ 'ecomm_prodid' ].push == 'undefined' ) {
				return false;
			}

			var productdata;
			$( '.gtm4wp_productdata' ).each( function() {
				productdata = jQuery( this );

				dataLayer[ i ][ 'ecomm_prodid' ].push( '' + productdata.data( 'gtm4wp_product_id' ) );
			});
		}
	})(jQuery);
</script>

Is this a bug of the plugin or am I missing something?
Note that I have CloudFlare active.

Thanks
WP-OK

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