Can I do a VAT adjustment to reduce Output VAT due in the next quarter as I need to write-off some bad debts that aren't on Quickbooks

We've got two options for this, stephen13.

First, you need to record the bad debts in QuickBooks for them to reflect on your VAT return. With this process, you don't need to do an adjustment. You can check this link for the step-by-step procedure in writing off bad debt in QuickBooks Online.

Another option is to do the adjustments on the VAT return without recording them in QBO. But we would suggest that you reach out to your accountant as we are not trained accountants here. This is to make sure everything is recorded properly and to avoid messing up your books or amounts on your return.

I'm including these articles that deal with VAT in QBO:

• Adjust your VAT liability.
• VAT: Getting Started.
• Submit a VAT return in QuickBooks.

I'll always be around if you need more help in dealing with your VAT in QuickBooks and other related concerns.