Good idea spreading the side load between the bulkheads, I didnt think of that. But not sure how well a bolt in each end would work as the shaft would be spinning.

Say I put a 10mm thread in each end and put a 10mm bolt through the retaining plates I already have there. That would do it maybe??
Hinm i would need a bearing in between the bolt head and plate though otherwise there's a chance the bolt would undo due to the spinning shaft.