How do I determine the date of supply for continuous supplies of goods and services?

Continuous supplies of goods and services, and the payment for these supplies take place over a period of time. The date of supply for every individual payment is when the payment is made or when the invoice is issued (whichever comes first). 

If you haven’t issued an invoice or received any payment for an installment, then the date of supply will be the later of either:

• at the end of 12 months after the date the supply started, or
• the date of supply for the previous supply made