Thanks Walter,
I have the IAM permissions in place and also have a valid billing account.
However, I keep getting the same error regarding the missing Marketplace token. I am clicking the 'SIGN UP WITH DATABRICKS' button from the GCP UI, so am not sure what's causing the issue.
I have tried with multiple browsers (Chrome, Brave and Edge) and also multiple laptops, but keep getting the same error.
Would there be anything else I can try?