How do I show a supplier giving us a credit note for opening account?

I opened an account with a supplier, and they provided a credit note of £12 to our account without us even ordering anything! How do I show this in QuickFile, please?

You may find the posting below useful:

No need to record any thing until you actually make any purchase from them, once you record purchase and time to pay just enter normal discounted payment from bank or cash and record the difference as discount income

OK; thanks for your help!