I totally understand your concerns about shipping and import taxes when buying a product from the US to the UK after Brexit. I did some research and found some helpful information on https://www.paystubcreator.net/ that might be helpful for you. According to their website, UPS charges a brokerage fee, customs clearance fee, and applicable duties and taxes for international shipments. You can also check with UPS for more information on their specific charges, but it's always better to be prepared for additional costs.You can also check with Kemper if they have more information