Well well well :o I'm gonna bury the treasures right now! Here's the map, not so good though. The treasures will be buried at 'landspots', like near a dock, under a tree, etc. Some treasures might be smaller then others :o
A bag with money and gems is hidden quite a bit south of Pirton, near a well...
A bag with coins is hidden near the windmill in Milton, and
the last bag with a magical weapon is hidden in the north-east of the island, right of a row of fortifications.
Good luck finding
four bags have been found!