And I cant for the life of me remember where it went
Its not like any of the other snap rings where the tips are pointy. This one looks like this:

Bit of a long shot - but does anyone have any suggestions or idea's where this might go?
Oh yeah - and as you can see there is a wear mark on the outside of one side, and on the other side, the wear mark is on the inside......Not sure if that means anything.....