I need a Wordpress plugin tweaked

I am seeking an experienced WordPress developer to enhance an existing plugin on our website. This plugin facilitates customer address selection for product delivery and collection, with pricing adjustable based on eight predefined locations. However, we face a challenge: our products are stored in multiple locations, necessitating a more dynamic pricing structure. For instance, if a customer in Edinburgh orders product A from London, the delivery charge should reflect the distance, whereas product B, stored in Edinburgh, should incur a lower fee. The goal is to allow each product to be linked to its respective location to streamline this process effectively.

PLEASE NOTE THIS IS NOT A WOOCOMMERCE PLUGIN. It is a bespoke plugin that the developer has limited functionality to a business based at one site, although it already allows for many additional sites for collection points. We operate from different sites and need to reflect this for our customers. (i.e. if they want a product located in London to be delivered to London it will be a relatively small delivery fee, compared to the same customer wanting a product located in Dublin.