Unable to display custom fields on WooCommerce product pages

I've set up some custom fields using the existing 'custom fields' panel on a WooCommerce product page. I'm unable to display these on the front end. My technical knowledge is limited but I've tried every example and code snippet found elsewhere on this site, including;

// Display Custom Field Value echo get_post_meta( $post->ID, 'field', true ); and a bunch of others.

However, when I use

get all meta? which, from what I understand, should display all meta, it gives me this on the front end;

frs_woo_product_tabs: a:1:{i:0;a:3:{s:5:"title";s:12:"License Info";s:2:"id";s:16:"tab-license-info";s:7:"content";s:19:"License description";}}

It doesn't appear to recognise any of the custom fields that I've entered. Am I missing something obvious?