well I dont metal detect....but you're going to hate me for this Toddy
If I found that site with its lovely quern and stories from Bce, and it had a pot of gold in it, I would have ripped the whole damn place up and made off with it. And the end of the day learning about what we did thousands of years ago is nice, fascinating and awe inspiring, but not as much fun and awe-inspiring as the experience those bits of metal can buy me!
Indeed it is selfish, but like I said, if the reward for handing it was as great as the blackmarket value, people would hand these things in. Instead it is taken from them, they are investigated every which way to see if the money has to be paid, and then you get about 10%.
I read a case in australia where some people found an ancient ostrich egg used by aborigine people thousands of years ago. The state said it belonged to them and they were not entitled to a reward. SO they reburied it, and good on them. Told the museum to go find it themselves.