BSA B40 SS90 Swing Arm

[MickG]

Hi Guys,
Can anyone tell me the inside measurement where the wheel mounts on a BSA B40 SS90 swinging arm.
I believe mine is bent and the frame drawings I have do not show the swinging arm.
If I remove one of the inner axle nuts the wheel fits in but not with both or any washers.

Cheers,

MickG