Hi @Warmergroup
Welcome to QuickFile!
You’re correct with what you say about supplier credit notes cannot be created without an invoice, however there are a few ways this can still be achieved.
I’d recommend taking a look at these posts. In some cases, they may refer to clients, but the client and supplier interfaces are very similar:
http://community.quickfile.co.uk/t/enter-opening-credit-notes-without-depositing-to-the-bank/186/2?u=qfsupport
http://community.quickfile.co.uk/t/setup-an-opening-client-credit-balance/11732/2?u=qfsupport
Please let me know if you need any further help with this, and I’ll certainly try my best! 