Reversing slightly wonky?

[Fiend]

My Savage is always reversing wonky. I've trimmed the steering so it goes almost straight forwards (subject to, errr, user error), but on reversing it always steers to one side (right, looking forwards along the car). The rear wheels are slightly toed in (and thus toed OUT as the car reverses), which seemed strange to me but looking at the comparison of parts 105673 and 105675, that's how it's supposed to be.

Is there anyway to rectify that? Obviously there's a fair bit of play in the area due to various mishaps, but I'm not sure what could be done to tighten things up?