Dutch VAT numbers MUST have the format (NL123456789B12).
cac:PartyTaxScheme [normalize-space(cac:TaxScheme/cbc:ID) = 'VAT'] /cbc:CompanyID [starts-with(normalize-space(.), 'NL')]matches(normalize-space(.), '^NL[0-9]{9}B[0-9]{2}$')