Camera written off as defective within warranty period and supplier credit

That seems like the best way to me!You do need to be careful, though, because you haven't received a credit note and refund, but a credit balance. This means that you will receive a discount for that amount on your next purchase from the same supplier. However, this is of no accounting significance as long as you don't make that next purchase (and check how long that credit balance remains valid so that it doesn't expire before you can use it). For the time being, you do not have to enter anything in your accounts and you have lost the expense (it has been paid, invoiced and entered in the accounts, but it is of no use to you). In my opinion, this is also contrary to the European warranty regulations. In the event of a fault within the warranty period, the supplier is required either to refund the purchases in full (and therefore also to issue a credit note) or to provide a replacement device free (the supplier is also responsible for the shipping costs).