I'm just glad that a major, game-wide event will finally be coming to Serpent's Hold. (Serpent's Hold is the classical location of the Bell of Courage. It was given to the Order of the Silver Serpent to guard there, after which they built the Hold's fortifications to protect it. We have a bell-tower-looking thing on top of the main building on the north island for ringing it, but the Bell itself is usually kept safe in a hidden underground location deep within the Hold.)
If I recall correctly, the Bell of Courage, and indeed all three artifacts of principle, were introduced in Ultima 4. The Bell, much like Mondain's skull, was found in what they called a deep well. It was actually located out in the middle of the ocean south of Magincia while Mondain's skull was located east of Serpent's Hold in the ocean surrounded by three volcanoes.
Now in Ultima 5, both locales were replaced with islands. Blackthorn's castle was built upon the volcanic islands where Mondain's Skull had been found while Sutek took refuge on the swampy isle that appeared where the Bell had been found.
In Ultima 6, Sutek went mad and took refuge in Blackthorn's abandoned castle while his former home, the swampy isle, became the refuge for a band of pirates who buried their treasure in underground caves.
At any rate, one could argue that the swampy isle from the original Ultima games is Haven/Ocllo in UO. Perhaps the well the Bell was stored in is in actuality the inland lake (now a bay). There was, after all, an odd wooden structure which spanned the lake and it was interesting that at the center of the structure (the center of the lake), there was a railed opening providing access to the water. Perhaps those who hid the Bell brought a winch to that spot to lower the bell into the water and could later retrieve it in a similar fashion. Of course, the structure is demolished, but is the Bell still hidden beneath the waters there?