I also have a new croll and find it turns when loaded im also not convinced on the new steel plates on the alloy with those two not react and cause the alloy to corrode?
Having just used a new Croll in a rope-access sit harness configuration for a week, and with no problems with the device sitting flat against my chest, owing to the sewn strap and delta Maillon that holds it in place, I'm now convinced there's a problem with the bend in the plate on the caving model, or at least the mounting configuration it requires. I used it again in a shaft last weekend, and at the rebelay, predictably, the catch got stuck in my ribs, just like it always does. I showed the rotation issue to my colleague when I got out, and he agreed that it didn't look right at all - its resting state is about 5 0'clock when viewed from above.
The two metals will only react corrosively when permanently exposed to moisture over a prolonged period, so as long as it's dried out after every trip, that shouldn't be an issue.
G Force make (budget) work at height kit and I've used this supplier for lifting slings before. Budget work at height kit really doesn't look very polished most of the time, not if you are used to Petzl and DMM's kit anyway. When I have some money in the slush fund I might grab one to see what it's like. I don't need a lefty chest jammer, but it's always nice to have options for training courses.