Hi Sean,
Yeah, likely you'll need to find a developer to help assist with that since synching with eBay UK is not as prevalent from what we've seen. We have a connector that helps sync Shopify and eBay US only. I haven't seen any Shopify eBay UK but there might be one or two out there now. Eventually we will move into this direction but as of now you'll probably need to find a developer to help custom code this.
Best of luck.
Darren
