Just remove your standard bolts holding roll bar clamps, and put antidive metalwork between the roll bar and bodywork where the original clapms bolted.
Use the original holes to hold antidive metalwork, then use the wider clamps of the new antidive metalwork to bolt roll bar to.
Anti dive nothing to do with rear axle as it is at the front.
The bars that you refer to at the back are locations bars to stop the axle moving sideways, as as std they did not use a panhard rod or anything, a truly shit design without one.
tabetha