I am an American living in Scotland and I wish to sell some items on eBay. I have a UK registered eBay account with my UK address. It did ask me my nationality, which I put down as USA. When I attempt to sell items it adds VAT to my listings, which I understand would make sense if I were still living in the States and trying to sell items in the UK. But I am a UK resident (have been for three years, plan on staying permanently) selling a used item I originally bought in the UK and paid VAT...

Are you sure it is VAT (which is 20%) and not the Buyer Protection Fee - which is considerably less. How much did you actually list the item for?

UK Resident being charged VAT on used item purchases | Member To Member Support

UK Resident being charged VAT on used item purchases | Member To Member Support | eBay UK