ERROR: 'One or more of the selected items are allocated therefore cannot be deleted.'

You see this error when you saved the supplier payment to the supplier's account first, then allocated it to an invoice later.

To delete the payment:

1. Break the supplier allocation.
2. Then, delete the supplier payment.

ERROR: 'You cannot delete VAT reconciled transactions.'

You see this error when you use the Cash Accounting VAT scheme, because supplier payments appear on the VAT Return.

If the payment is on a draft VAT Return:

1. Delete the VAT Return.
2. Then, delete the supplier payment.

If the payment is on a submitted VAT Return:

Reverse the payment instead. You can only reverse a payment that doesn't pay an invoice, so you may first need to unallocate the payment from an invoice.