Good afternoon @tracey2972 

Use Z=0% or Exempt - both have the same effect on the VAT Return.

Do not use NoVAT - that code does not record to the VAT Return at all.

Do not use any of the EC/EU VAT codes - unless you're in Northern Ireland they are no longer relevant but QB seems to insist on keeping them (which would be OK if the information about them was updated).

Hope this helps.