Rear Hub Rotating in Drum

I've just fitted some new mags and I've noticed that the rear wheels are able to move slightly with the handbrake on. I've taken the wheels off and had a look and it appears the hub with the stubs can rotate and jiggle around a bit whilst the actual drum isnt moving. It's actually quite pronounced on one side, you can hear it jiggle when you drive. This can't be normal. I've installed longer stubs but that hasn't fixed the problem much.

Is some level of movement normal? Cheers.