Split hub wheel wobble

[Cotmullion]

I have two split hub 10 inch pnuematic tyres on my minibike and they wobble because the bolts are not tight enough. However the bolts are hard to do up tighter because two have been replaced with longer ones which attach to a peice of flat section which has a hole going through it, which the axle goes through and is welded to, to make it live axle. Also, one other one of the bolts has striped its thread and is hard to get out and almost imnpossible to do up or undo. It wobbles but isn't unstable, and the sprocket is straight, because it is fixed to the (live) axle, not the wheel, so at the moment I am leaving it, unless anyone has another idea.

 

[Cotmullion]

Here's a few more pictures showing the wheel, and how in is attached, to try and make it seem clearer and less confusing. I am just not sure if the wobble is going to be a problem. Is it a problem?