Lay-buy or deposit handling

If a customer pays you a deposit or lay-buy instalment, record it as a partial payment against the full invoice.

1. Issue the invoice for the full amount
2. When the first payment lands, go to Bank Transactions and match it to the invoice as a partial payment
3. The invoice status updates to Partially Paid
4. Repeat as each instalment comes in
5. When the final payment is matched, the invoice moves to Paid

This way the full sale is recorded against the right period for tax purposes, and you track the outstanding balance cleanly.