I worked on a house in Castle Bank behind Lewes Castle & while digging under the walls to underpin them, we came across a well, mostly under the house next door, it had been backfilled at some time, but I measured down from the basement floor, & it was 2.6metres to the backfill & 800mm across, we decided to put a time capsule down there ( a stainless steel flask with a note & some money from our times, ) ( I actually put a fake £10 note in it, telling the other lads not to be stingy) before we underpinned that part of the wall. I haven`t come across any evidence of documentation of the well, but I have heard about the capped off one on the top of the mound.