To deal with this in Navigator, you'll still need to close your VAT return on Navigator.
This will post the VAT payment into your bank, however, this can either be left as a unpresented payment on your bank, then reconciled when it is due to be paid.
Or a new nominal can be created to journal the payment to, this can act as a holding account and has to be set up as a LIABILITY.
Once the payment needs to be paid, this can be journaled out of the code you've created above, to your bank.
*payment holidays are arranged with HMRC and not through Navigator