The issue is that no one can actually accurately determine the...

The issue is that no one can actually accurately determine the value of the any brand that has been internally generated. This is the reason why internally generated goodwill (such as a brands) cannot be recognized on the balance sheet (as per AASB 138, para. 63).

Therefore I believe if a bank was to loan against an intangible asset, it would more likely be one that was recognized on the balance sheet. I doubt a bank would accept unrecognized internally generated intangible assets as collateral. However as I don't work for a bank, I can't say for certain.