Heres a couple of finds my daughter has found recently.
Royal navy Captain/commander or Lieutenant button from around 1787. The back still has its shank intact and reads "Standard Colour". A crown was added above the anchor on these buttons from 1812, so its defiantly pre 1812. I have put a 1p in the picture for size.
She has also pulled up a Qing (Ch'ing) Dynasty coin from 1736-1795 with a square hole in the centre, this has slight damage of this centre square.
These are her best 2 finds so far and she is very proud. Considering I have been over and over these fields, they are still producing some good bits. Hopefully there is a lot more to come