Buying tiles in the EU and take it into the UK for "personal use"

I have been refitting my house in the UK. The tiles I need are almost unavailable in the country, and where I could buy them, they were more than twice as much as in the EU. These tiles are made in Poland. I would buy and take them. I can see there is a 630 GBP limit for the online simplified rate. BUT is this netto or brutto? Because the final price is around 600 + VAT. The netto price is below the limit, the brutto price is over the limit. In which country do I have to pay the VAT?