The cache is not at the listed coordinates.
The General Post Office is an impressive building in the centre of George Town, Cayman Islands.
An ideal place for a letterbox cache, this is the site of many letterboxes! Unlike the UK, where post boxes are bright red, here in Cayman they are aptly a bright Caribbean blue colour! There is one outside the front of the Post Office should you wish to take a look.
But this is a "letter"box cache, not a "post"box cache! Whilst most people get their mail delivered to their door (and quite often through a letterbox in the door), there is so such similar service in the Cayman Islands. Instead, residents must hire a box to receive their mail and check it regularly to see if anything has arrived. There are several places around the island where mail is received, but they can be in high demand! You will notice many rented letter boxes here at the listed coordinates, which will give you the final location for this cache.
N 19° 17.ABC' W 81° 22.DEF'
KY1-1102 AB (x=1; y=4) - (x=8; y=1)
KY1-1103 CD (x=1; y=3) - (x=11; y=1)
KY1-1104 EF (x=2; y=3) - (x=6; y=2), then divide by 2
Please note, this is a letterbox cache. You can record your log in the book as a stamp, or signature if you prefer, but please leave the stamp paraphernalia as part of the cache content.