Yes!
If you are not VAT registered, the VAT breakdown that appears on the Quotes and Orders won't be relevant to you.
To remove this, in Once Setup press this button
to open the Quote and Worksheet Template Editor.
Go to the BusinessVATNum field, double-click in the Value column next to it, and delete all the text in that field. (see the red circled area in the screenshot below)
If there is no reference to VAT number here, no reference to VAT will be made on the Quotes and Orders created by Once Mobile.
Remember to press the Upload to cloud button 
when you're finished, and in Once Mobile you'll need to press the Check for New Data button on the Settings screen to pick up the changes.
