Delving back into the dim and distant past - inside the final drive from the left hand side and accessible only when the wheel has been removed, is a spacing tube. It is quite long and sometimes drops out with the removal of the wheel. Often it stays in place and you don’t even know that it is there.
The end is visible inside the female final drive spline. It will pull out with fingers quite easily. On the fiche for the final drive it is referred to as a distance collar.
If I remember correctly, the distance collar is not a simple tube. On mine, one end seemed to have a slight taper, and the surface on that end had a slightly rough texture. It fitted better one way than the other. I think that I had to put the tapered / rough end in first. If you get it in the wrong way round, the wheel cannot sit properly on the final drive splines and that results in a gap between the wheel and final drive housing - just like the one in your photo.
I had an 1100T and an 1100AY. Hopefully someone like
@Uncle Phil will be able to confirm or correct my 20 year old memory.
Edit
I found reference to it in an electronic manual - Part 28.
And in the assembly instructions:

Odd - it refers to the 'polished side'. Mine felt ground or textured rather than polished. Maybe a translation oddity ? It was definitley a short section at one end that was different and it inserted slightly further.
Whatever - I reckon that whichever way it is inserted now, it would be worth taking it out, checking it and putting it back the other way.