I noticed that the heavily tapered side was fitted towards the outer bearing - the flat shouldered side towards the inner hub bearing. I'm pretty sure this was incorrectly fitted by the previous owner / some mechanic.
The reason I think this is that that the tapered side wouldn't have seated against the inner race of the outer bearing properly - only partially seating at its widest point. Also the end of the none tapered side of the spacer is a good bit wider (30 mm) and when turned around fits snugly into the inner race of the outer hub bearing whereas the tapered side flops about loosely.
Can anyone confirm that I'm right and the tapered shoulder faces inwards towards the inner hub bearing. See pics.

