This one was a "must do" during the event - and it was on the way when solving "time and space". I went with RexTrex and quickly found GZ. However, then I did a lot of funny things Rex filmed with his Camcorder. I hope it won't be published . In the end, I found it, of course. Rex commented: "Ya, that's where I remember it was when I found it."
Thanks to Tankengine for the cache & Rex for not helping me - Fogg