Previous owner may have put it outside the bearing after changing wheel bearings- check if the spacer between bearings can move sideways by sticking a screwdriver or similar in to try to move it. It shouldn't be able to move much so the axle will slide straight in.Thanks for the reply, yes it may we'll be that, even though I'm almost sure I did not take the bearings out. I will have a look.
Here I think it shows on the 2011 570 FS parts, nb 8 ref 60010015000.