In this case Peter it was pot luck, but other reasonable finds have been made on this particular field, some Roman and also a poor Sceat as well as EdwardIII hammered and a Charles half groat, none of which I have seen. I personally don't research sites I just go on club digs but many people spend considerable time researching sites. To answer your first question, the thrill of finding something that was last held several hundred years previously and investigating it's history is my interest, I rarely look at coin displays unless they have been recently found. I have only ever sold one coin I found, this was a gold Quarter Stater, mainly because I was afraid of losing it. I once found a Victorian one eighth of a farthing, about the size of a nail head, it got lost in house moving or something. The same goes for a first edition Charles Dickens. I also found a uniface gold Stater and a quarter Stater on the same day in 1981, the landowner(now deceased) excercised his right to first refusal and he paid me for my share. My wife once found a double head silver Roman in Hampshire. Several dealers offered her silly money for it, then a dealer from Tyneside offered her £400 and she took it. The only find she ever sold.