Hello grrowlinglypurrf
Thanks for reaching out to the Community.As you can not turn of VAT once it is turned on in QuickBooks the best thing to do is to default NO VAT in the settings which will mean no VAT is calculated or shown on anything sent out.
To do this go to the cog in the top right>account and settings>advanced>accounting>default tax rate selection>change it to NO VAT>save.
Emma