Mapping to HPOS order tables

Been using the plugin for a number of years to map WooCommerce orders to a AusPost CSV template. The plugin has been working great but I have experienced a problem after updating our website to HPOS (High Performance Order Storage).

In order to make the CSV export work correctly I have some custom PHP functions that were previously saving values (cart weight, satchel size, etc) to the WordPress ‘wp_postmeta’ database table.

After updating our website to HPOS, I’ve had to modify our custom functions to now save to the new ‘wp_wc_order_meta’ instead of the ‘wp_postmeta’ table. I have checked the ‘wp_wc_order_meta’ table and the key/value are being saved correctly.?

However, in the Advanced Order Export plugin settings section ’Set up fields to export’, I now no longer have access to the custom database order values (cart weight, satchel size, etc). 

I do have ‘Enable compatibility mode (synchronises orders to the posts table).’ checked in WooCommerce setting – WooCommerce / Advanced / Features. 

Have I missed something here? Do you have a solution how I may access the custom values saved in the ‘wp_wc_order_meta’ database table so these may be mapped to a CSV export?