DaveCool: I checked on this at lunch today and found that it's time ran out. The cache was hidden in a large metal sculpture which was on loan. I think it had been there for years, but evidently it was called home. I'll look for an appropriate replacement location when it's warmer, or if anyone else wants to feel free. The staff were very friendly and receptive to the idea, so just be sure to ask permission.
DaveCool [8D]