Dear madam, sir,
Norway is not part of the EU, so this sale qualifies as an export sale, which sale is normally taxed with the VAT zero rate. Important for you is to have documents in your admin showing the actual export from the UK.
Such sale should be handled under the INCOTERM DDU (delivery duty unpaid). As a conseqence, your customer is liable for any duties that would become due upon importation in Norway. As Norway is part of the EER (European Economic Area), which means that in principle no customs duties will become due on the import of the goods.
Hope this helps!