I've used that expression many times successfully. Are you sure that GHCClogo is really a global field?
is the global field on a table with no records?
Having global fields on their own table can create problems if the table doesnt have at least one record.
As a test, you might change your expression to:
Case(True; GHCCLogo; "")
If you still don't get a logo, the problem lies with GHCCLogo--maybe it's not a global field, or maybe your result type isn't actually set to container.
If every record now shows a logo, the problem is with your GHCC field, maybe it has a non printing character like a space or something that's keeping GHCC ="GHCC" from evaluating as true.
It works - I couldn't see it until I viewed all records and went to Preview. I was so sure I had done all that already. But I was too quick to post.