npm install postcode-anywhere

var key '<YOUR_API_KEY_OBTAINED_FROM_THE_POSTCODE_ANYWHERE>'
var gateway = new Gateway( key );
gateway.bankAccountValidationInteractiveValidate( '<YOUR_ACCOUNT_NUMBER>', '<YOUR_SORT_CODE>', function(err, result) {
  console.log( 'ERR', err );
  console.log( 'RESULT', JSON.parse( result ) );
});