Raising credit notes using the Raise Invoices and Credits option

In the processing menu select "Raise Invoices and Credits" (Step 1)

In the Raise box select "Credits" (Step 1)
Ensure the "All Invoice Methods" and "All Invoice Types" boxes are ticked (Step 2)
Press Search button (Step 3)

Select the date you want the Credit Notes to be dated (Step 1)
Press the Select All button to highlight the transactions to be credited (Step 2)
Press the Raise Credits button to create the Credit Notes (Step 3)