Funny how some things just come together at the same time. There we were today, digging up more metal stuff, when this made an appearance:
A horse bit. Took a few in situ photos then back to work. A few minutes later I heard a voice and saw a horse with its head over the gate apparently saying "what are you looking for then?" Luckily for my sanity I then saw the rider. So we asked them in and I saw that the bit in the horses mouth was just like the one we had just dug up!
This style of bit makes the horses head turn better. The twist in the old bit is no longer used, as it hurts the horses mouth more. Synchronicity.