Inevitably I step in.. Because I've had half the car apart sorting noises.
The creak is most likely (and it took me years to find this) the metal piece that the rear clamshell roof sits on.
Under this plate is a number of plastic nuts and you can either tighten these or remove and grease the under side.
I think this metal plate vs plastic it sits on expands at different rates and add in pressure from the roof makes a clicking creaking noise.
That's my guess in this instance.