"I believed that it was a UK auction, no?"

DON'T KNOW, but why put a gun like that in a Swedish auction site when you have the biggest and the best auction houses in the UK ?

I still don't get how that auction is subject to UK VAT,
even if it was in the UK, if you are on OS buyer I have
never been charged VAT.

Same as if I sell something from here in Aus OS, I don't charge an overseas buyer GST.

.