Just after Brexit I experienced the attempted collection of VAT from a UK vendor. Turns out, they were merely acting as the middleman for the product that originated in the EU and so they had been charged VAT and were merely passing it along. I didn't order it from them, but instead, ordered it from an EU vendor and there was no VAT charged. In my instance, it seemed to be an issue between the EU source and the UK vendor. Not sure if it got sorted or not since I haven't tried ordering anything from them since.