Hi @Sam,
You missed the codes for the saving the custom field value. Please follow this article and find the missing code: https://pluginrepublic.com/woocommerce-custom-fields/
The customization codes are out of scope of our support standard service. Should you require further code customization, our team of expert developers is ready to assist you with bespoke solutions. For a detailed estimate and to discuss your specific requirements, please submit a request for customization services through the following link: [8Theme’s Customization Services](https://www.8theme.com/account/#etheme_customization_panel).
We appreciate your understanding and are here to support you with any additional questions or needs you may have.
Kind regards,
The 8Theme Team